Alternatives Search: Demonstrating Compliance

by Megan Van Noord – November 22, 2021

Searching for alternatives means considering ways to reduce, refine, or replace whenever there is proposed animal use in research, teaching, or testing. 

This guide focuses on the Animal Welfare Act (at left, August 1966) and US regulatory compliance in research and education.  It is, however, an international concern, and most countries have animal welfare laws and regulations that also require a consideration of alternatives.

Megan Van Noord

Researcher Services
Health Sciences Librarian


In this Guide:

1. Define the Questions

Note all possible keywords and subject headings to include in your literature search,  those which are related to your research, as well as those related to the 3Rs.

2. Select Appropriate Databases

Selecting the appropriate databases is critical; you will need to search in more than one database and to tailor your keywords, subject headings, and search strategies to each specific database.

3. Construct the Search Strategies

After developing keyword lists, you will need to develop search strategies, including how to expand and/or narrow your searches.  Keep a record of databases and search strategies for protocol submission.

4. Evaluate Search Results

Review and evaluate your results as you go along in order to make modifications to your search strategies.

5. Manage and Report Search Results

After conducting your searches, you will need a way to keep track of the information that you have located, document the process, and create a narrative concerning any refinements, reductions, or replacements identified.


Which is similar to the search approaches described in:


1. Define specific information needed
2. Identify fundamental components of scientific approach
3. Choose appropriate information resources
4. Compile search terms
5. Search in 3Rs-specific context
6. Limit search results in broader biomedical databases
7. Broaden the search as necessary

Article by Leenaars (Lab Anim, 2012)

1. Formulate research question
2. Identify appropriate databases and sources of studies
3. Transform research question into search strategy
4. Collect search results and remove duplicates
5. Identify potentially relevant papers

Article by Sargeant (Zoonoses and Public Health, 2014)

1. Define the review question
2. Conduct a comprehensive literature search to identify primary research studies
3. Select relevant studies from the search
4. Collect data from relevant studies
5. Assess risk of bias in relevant studies
6. Synthesize the results: Qualitative or quantitative (meta-analysis)
7. Present the results
8. Interpret the results


Additional Alternatives Research Guides

Highly recommended guides:  

CCAC 3Rs Search Guide  |  EUR ECVAM Search Guide  |  UCCAA   AWIC  |


European Commission EURL ECVAM Search Guide
… a fundamental requirement, namely that, for legal, ethical and scientific reasons, any researcher planning to, or using, animals for experimental or other scientific purposes must be well-informed about the state of the art of the proposed field of investigation.  In particular, to satifsy the legal and ethical imperatives that animals shall only be used for research and testing if all possible alternatives are considered but found to be inadequate…


This guide based on work previously done by:
UNC  |  University of Denver  |  University of Toledo  |


Terms and ideas from proposed study, possible search terms, possible search questions:

Reading through the protocol, make notes of terminology, procedures, drugs, considering what questions need to be asked related to replacement (model choice/necessity), reduction (unnecessary duplication, study design), and refinement (methods/procedures potential pain/distress), and current best practice/SOP/guidelines.

Questions to be searched common to all protocols:

Is the proposed research necessary, what has already been done in this area, what models have been used, what best methods/procedures, and alternative consideration for potential pain and distress

  • List every procedures in the protocol that has the potential to cause pain or distress.
  • Identify other possible terms for each technique that you have identified; determine if a subject heading for each procedure exists in the database that you are using.
  • Search each of these procedures, considering alternative methods to accomplish the same goal.
  • Begin by searching broadly for each technique. Next, try combining each technique with some of the keywords and subject headings for pain/distress prevention and control, analgesia/anesthesia, and refinement as listed in keywords and in the search examples.

Formulate the Questions

for example:

What is the effect of [intervention/exposure] on [outcome measures] in [animal species/population] for [disease/health problem]?

How to teach [procedure/technique] to [population]?

Consider the research-related terms
Scientific, common names of any species
Scientific, common names of any diseases, conditions
Generic name, trade names of any drugs, chemicals
Scientific, common terms for tissues, systems, or cell lines
Treatments, procedures

Note keywords and synonyms
It is important to record these keywords at the beginning of your literature search so that you are able to both be consistent across searches and provide the required narrative account of your literature search in your protocol. If you make changes or additions to your list of keywords, include those changes in your records.

3Rs-related keywords
There are many options for keywords in the 3Rs. When choosing keywords, it is important to know if the specific database has a special vocabulary – it may index one keyword but not its synonym. It may also require you to put your keywords in a specific format.

For example, PubMed’s subject headings, MeSH, are different from that used by CAB or AGRICOLA.


Reduction and Refinement keywords

Analgesic, hypnotic, sedative, tranquilizer
Anesthesia, anaesthesia
Assay, technique, method, procedure
Enrichment (behavioral, environmental)
Experimental design
Handling, housing, husbandry, caging
Invasive, non-invasive
Monitoring device
Positive reinforcement
Postoperative, postsurgery
Reduction, refinement
Restraint, restrict, immobilize
Train, educate, teach, instruct
Welfare, pain, stress, distress


Replacement keywords

Algae, fungus, hydra, plant
Anesthesia, anesthesia, anaesthesia
Animal testing alternatives, alternative
Artificial intelligence system, AI
Assay, technique, method, procedure
Autopsy, biopsy
Bacteria, microorganism, protozoan, 
single-celled organism, yeast
Cell, cell line, cellular
Computer aided instruction,
computer assisted instruction, CAI
Culture (cell, tissue, organ)
Digital imaging
Environmental enrichment
Fish, cephalopod
Insect, invertebrate
Isolated (cell, tissue, organ)
Mannequin, manikin, manikin
Membrane, organ, organelle, slice,
tissue, tissue equivalent
Model, modelling
Physicochemical systems
Replacement, surrogate
Simulation (computer)
Structure-activity relationship
Train, educate, teach, instruct
Virtual (surgery, reality)
Vitro (AND method, model, technique)


Related resources

USDA’s Policy #11: Painful and Distressful Procedures  Defines a painful procedure as “any procedure that would reasonably be expected to cause more than slight or momentary pain or distress in a human being to which that procedure is applied, that is, pain in excess of that caused by injections or other minor procedures.”
USDA’s Policy #12: Consideration of Alternatives to Painful/Distressful Procedures  Details the requirement of considering alternatives to painful and distressful procedures, recommending a database search as the most effective method to determine alternatives.
Animal Welfare Act – Requirements for the Minimization of Pain and Distress
W.R. DeHaven summarizes the requirements of Policies #11 and #12.

AWIC’s Pain and Distress page  List of resources about pain management, alleviation, humane endpoints, and refinement techniques in various species


Assessment of potentially painful procedures

Refinement of animal use-assessment and alleviation of pain and distress Paul Flecknell, reviews methods of clinical pain assessment in animals and techniques for pain alleviation.
Recognition and Alleviation of Pain in Laboratory Animals National Research Council (US) Committee on Recognition and Alleviation of Pain in Laboratory Animals.  Table 1-1 of this resource lists examples of painful procedures or conditions by type and anatomic location.
Seminal work on rationale on reducing pain and distress to experimental animals. This book introduced the 3Rs.
Wiley’s Current Protocols

Covers over 20,000 updated, peer-reviewed protocols. UCD Library subscribes to 13 major laboratory methods and protocols series including Current Protocols in Molecular Biology 

Springer Protocols

Contains more than 34,000 molecular biology and biomedical peer-reviewed protocols, mostly from Methods in Molecular Biology. 

Cold Spring Harbor Protocols

Research techniques database with specific sections on Antibodies, Bioinformatics/Genomics, Cell Biology, Chromatography, Computational Biology,  

Nature Protocols

Interactive online resource for experimental and laboratory protocols for bench researchers primarily in biology and chemistry 

JoVE - Journal of Visualized Experiments

Peer reviewed, PubMed indexed journal devoted to the publication of biological, medical, chemical and physical research in a video format 

Methods in Enzymology

Classic laboratory methods series, contains detailed protocols and descriptions of biochemical and biophysical techniques for research in biological and molecular sciences 

OpenWetWare Protocols

Open access to full-text protocols in three categories of “in vivo”, “in vitro” and “in silico” and a general category of other  


Peer-reviewed, life science protocols organized by 11 different fields of study and 10 different organisms  

Selecting Databases for 3Rs Searching : Database Selection Tips

Select the databases according to the study and particular question being asked.

Databases vary by the type and number of records they contain, their dates of coverage, the formats of literature they consider (i.e., chapters, articles, proceedings), and the scope.

When searching for animal research alternatives, it is very important to look in more than one database. While your first instinct may be to look only in PubMed, there are a wide variety of other options that will usually give you different relevant results.

Most researchers choose to start with PubMed or another broadly inclusive biomedical research database (i.e., Scopus, Embase, Biosis).  Your additional databases can be a second biomedical research database, or focus on a specific aspect of the protocol design, the animal model, the 3Rs, or other funded research

If there is a specific database relevant to the protocol topic or model, you should include it in your search.

Further Help

You are welcome to contact a health sciences librarian for assistance in selecting the most useful databases for your protocol.


Database indexes resources in all aspects of agriculture and allied disciplines including animal science, veterinary science 

ASFA - Aquatic Sciences and Fisheries Abstracts

Database on the biology, ecology, technology and management of marine, freshwater, and brackish water environments and organisms


Life sciences, biochemistry, biomedicine, biotechnology, ecology, environmental sciences, genetics, microbiology, veterinary medicine & pharmacology, and zoology  

CAB Abstracts

Citations and abstracts to the international agricultural literature, including veterinary medicine, human and animal nutrition 

CINAHL Complete

Nursing, biomedical, allied health and consumer health literature 


Comprehensive bibliographic database of engineering research literature, containing references to over 5000 engineering journals and conferences.


Biomedical and pharmacological database  derived from biomedical articles in peer reviewed journals 

ERIC - Educational Resources Information Center

ERIC databases indexes and abstracts education and education related journals, studies and reports, with links to full-text studies and reports 


A comprehensive index to the global journal and proceedings literature in physics, engineering, computing, and information technology 


Citations and abstracts for articles published in  journals in medicine, life sciences, health administration, veterinary medicine, nursing, molecular biology and genetics 


Citations to articles in professional journals, conference proceedings, books, reports, dissertations 


Comprehensive bibliographic database for scholarly research covering all aspects of chemistry, including chemical aspects of biology and life sciences, engineering and materials 

Sociological Abstracts

Sociology and related disciplines in the social, behavioral, and cultural studies 


Information in all areas of toxicology, including chemicals and pharmaceuticals, pesticides, environmental pollutants, and mutagens and teratogens; is part of TOXNET  

Web of Science Core Collection

Broadly interdisciplinary, offers journal content across the humanities, social sciences, and natural sciences 

Zoological Record Plus

Database of animal biology, comprehensive coverage of zoology 

Altweb Site for news, information, discussion, and resources from the field of alternatives to animal testing

ANZCCART Australian and New Zealand Council for the Care of Animals in Research and Teaching. Many useful resources including Fact Sheets, Newsletters, and publications.

AWIC Animal Welfare Information Center Site for information for improved animal care and use in research, teaching, and testing

CAAT Center for Alternatives to Animal Testing. Johns Hopkins University Global resources for the development of replacement, reduction and refinement alternatives for research and testing

CCAC 3Rs Mircrosite Canadian Council on Animal Care – Replacement, Reduction and Refinement Alternatives

FRAME Fund for the Replacement of Animals in Medical Experiments (UK)Researching alternatives to animal use in research, testing, and education

Go3R Database acts as a filter applied to a PubMed search, simplifying retrieval of journal articles related to both the research topic and the 3Rs.

IACUC.ORG An information resource for members and staff of institutional animal care and use committees. It is a link archive, organized by menus and submenus, produced by the American Association for Laboratory Animal Science (AALAS).

ILAR Institute for Laboratory Animal Research prepares authoritative reports on subjects of importance to the animal care and use community and serves as a clearinghouse for information about animal resources

JAX Mice Databases Mouse Model Lists, Inbred Strains of Mice and Rats, Mouse Genome Database, and more.

Mouse Biology Program UCDavis, provides links to internet resources and databases for transgenic and targeted mutation research

NC3Rs UK-based National Centre for the Replacement, Refinement & Reduction of Animals in Research, Resources, Microsites, Hubs particularly useful.

NICEATM / ICCVAM NTP Interagency Center for the Evaluation of Alternative Toxicological Methods / Interagency Coordinating Committee on the Validation of Alternative Methods

NORINA Norwegian Inventory of Alternatives. Norwegian Reference Centre for Laboratory Animal Science and Alternatives Database of audiovisuals, computer programs, CD-ROMs, interactive videos, and other alternatives for use in the biological sciences

RePORTER NIH Research Portfolio Online Reporting Tools Expenditures & Results Searchable database of federally funded biomedical research projects

3R Guide Norecopa, in collaboration with the Animal Welfare Information Center has produced a database which provides an overview of guidelines, databases, journals, email lists, regulations and policies which may help researchers to implement the 3Rs when planning research that may involve animals.

3Rs Centre ULS The 3Rs-Centre Utrecht Life Sciences (ULS) stimulates the development, acceptation and implementation of 3Rs methods (replacement, reduction and refinement of animal experiments). Two databases: the Interspecies Database ( and the Humane Endpoints website (

Public Access Databases

AGRICOLA Produced by the National Agricultural Library

ALTBIB Bibliography on Alternatives to the Use of Live Vertebrates in Biomedical Research and Testing, National Library of Medicine

CRIS Current Research Information Service; USDA’s reporting system for ongoing and recently completed research projects conducted or sponsored by USDA research agencies, state agricultural experiment stations, the state land-grant university system, other cooperating state institutions, and participants in USDA-administered grant programs.

ECOTOX Ecotoxicology Database for locating single chemical toxicity data for aquatic life, terrestrial plants and wildlife; maintained by EPA.

DTIC Defense Technical Information Center (DTIC) serves the Department of Defense (DoD) community as the central resource for DoD and government-funded scientific, technical, engineering, and business related information.

PubMed Produced by the National Library of Medicine

TOXNET Produced by the National Library of Medicine. A cluster of databases on toxicology, hazardous chemicals, and related areas

ZFIN Zebrafish Model Organism Database of online information for zebrafish researchers

  • Formulate your research question: write out your research thesis as completely as possible. If there are multiple objectives, write a statement for each one
  • Break the question down into various concepts; do this for each research question you developed, above
  • Identify synonyms: for each concept, list various synonyms

After considering your search questions and identifying keywords and synonyms, you have chosen databases that index the information that may provide the answers to your questions.  Constructing a search strategy is dependent on the question, the terms, and the database.  Databases vary by the type and number of records they contain, their dates of coverage, the formats of literature they consider, and their scope. Databases also vary in how they index and their use of controlled vocabulary, like subject headings or a thesaurus.

Keywords can be combined with subject headings or defined terms, for example, in order to increase the precision of the search. Many databases have help pages explaining their specific features; please contact a librarian with any question at all.

To combine terms, use of Boolean logic: using the connector terms AND, OR, & NOT to structure your search query.

  • AND requires that both keywords appear in the same document;
  • OR requires that one or the other keyword appears;
  • NOT requires that the keword is absent.

Use parentheses ( ) to nest concepts together.

Truncation: search for multiple keywords with the same root by using a truncation symbol such as * or ? at the end of the root (ex: using handl* will find handle, handled, handler, handles, and handling). Check what the truncation symbol is for whichever database you are searching by checking the help pages

Phrase searching: For two or more words that are almost always next to each other, you can force most databases to search for them as a phrase by surrounding them with double quotation marks.  For example, “blood sampling”

Subject heading searching: Subject headings, a system of controlled vocabulary used to classify information into specific categories, provide a very powerful way to locate focused, on-topic results. The articles in PubMed, for example, are classified using Medical Subject Headings, or MeSH.


Considering Reproducibility, EBM and SR

ILAR Roundtables
ILAR Roundtable on Science and Welfare in Laboratory Animal Use
Institute for Laboratory Animal Research
National Academies of Science, Engineering and Medicine;

Reproducibility Issues in Research with Animals and Animal Models
Transportation of Laboratory Animals
Design, Implementation, Monitoring and Sharing of Performance Standards
Gene Editing to Modify Animal Genomes for Research – Scientific and Ethical Considerations

OHAT Systematic Review
National Toxicology Program (NTP)
Office of Health Assessment and Translation (OHAT)

Systematic reviews of preclinical animal studies
Marlies Leenaars, SYRCLE (Systematic Review Centre for Laboratory animal Experimentation)
Radboud University Medical Center, Nijmegen, The Netherlands
Cochrane Community Archive

Experimental Design Assistant – EDA
The Experimental Design Assistant (EDA) is an online tool to guide researchers through the design of their experiments, helping to ensure that they use the minimum number of animals consistent with their scientific objectives, methods to reduce subjective bias, and appropriate statistical analysis.
Cressey, D.  Better design for animal studies: Web tool aims to reduce flaws in animal studies. Nature. 2016. 531(7592)128.


Search Strategy: PubMed MeSH and Searching Examples

When searching PubMed it is helpful to use the Medical Subject Headings (MeSH) to find relevant articles. MeSH headings are assigned to each article within MEDLINE by its staff and are intended to be consistent across articles. This allows them to return more relevant and consistent groups of articles when searched.

Selected MeSH

“Animal Husbandry”[MeSH]
“Animal Testing Alternatives”[MeSH]
“Animal Use Alternatives”[MeSH]
“Animals, Laboratory”[MeSH]
“Animal Welfare”[MeSH]
“Housing, Animal”[MeSH]
“Investigative Techniques”[MeSH]
“Laboratory Animal Science”[MeSH]
“Models, Animal”[MeSH]
“Research Design”[MeSH]
“Stress, Physiological”[MeSH]
Using MeSH
MeSH terms can be combined to produce generalized searches for major topics in animal testing, including the health, welfare, and housing of animal subjects. Listed below are some sample searches for major issues of interest in your literature search.
Transgenic Mice:  mice, transgenic”[MESH] AND (“animal welfare”[MESH] OR “Animal Testing Alternatives”[MESH])
Suggested MeSH for: Replacement
To exclude animals and humans:
your topic/objective NOT (“Animals”[Mesh] OR “Humans”[Mesh])
To include possible non-animal models/methods:
your topic/objective AND ((“Models, Theoretical”[Mesh] NOT “Disease Models, Animal”[Mesh]) OR “Computer Simulation”[Mesh] OR “Cadaver”[Mesh] OR “Culture Techniques”[Mesh] OR “Cells, Cultured”[Mesh] OR “In Vitro “[Publication Type])
To exclude mammals:
your topic/objective AND “Animals” [Mesh] NOT “Mammals”[Mesh] .


Suggested MeSH for: Refinement
To minimize pain:
your animal type and/or procedure AND (“Central Nervous System Depressants”[Mesh] OR “Sensory System Agents”[Mesh] OR “Anesthesia and Analgesia”[Mesh])

To minimize complications:
your animal type and/or procedure AND (“Intraoperative Complications”[Mesh] OR “Postoperative Complications”[Mesh] OR “Perioperative Care”[Mesh])

To improve animal welfare:
your animal type AND “Animal Welfare”[Mesh]

When evaluating your alternatives searches, there are a number of questions you can ask yourself to evaluate the progress of your literature search.  The answers to the questions will help you determine whether your search is complete or whether you need to continue.

How many citations did I find?
If you have found too few citations, consider searching more databases, broadening your search terms, or searching a larger time span. If you find too many citations, perhaps you can limit or narrow your search terms to be more specific.

Are my keyword terms related to my protocol?
Make sure that the words you use to search are relevant to your research – otherwise you will end up with results that are not useful to you.

Are my keyword terms appropriate for the databases I searched?
Some of the best databases use subject headings that can affect your search. For instance, PubMed uses the MeSH term “neoplasm” instead of “cancer”. Other databases may focus more on common language terms.

How many places did I look?
Because the literature on animal research methods falls into so many different interdisciplinary areas, it is necessary to search more than one database. This is because no one database contains all of the information available on any given topic.

Did I set up my search strategy appropriately?
Databases may return odd results because they are confused by how you formulated your search. It will help to check the search tips or help pages in unfamiliar databases for strategies unique to the database.

Is the database you are searching the best for your research?
You may need to select different or additional ones.

Is your search query too long?
Every word you include narrows your search results because the database will try to find all of them in every record returned. Try shortening your search query.

Do you have multiple words that mean the same thing in your search?
Frequently, an abstract or article will use one synonym but not another, meaning that if you include both in the required search terms, you will cancel out finding the article. Overcome this by using Boolean OR.

Are you using Boolean terms correctly?
If you are using Boolean AND or NOT without using parentheses, you may be telling the database to limit your search more than you would like.

Are you searching an adequate time period?
This sort of literature search should include a broad period of time, with at least five years included.

Did you search in enough sources?
As the literature on animal research methods falls into so many different interdisciplinary areas, it is necessary to search more than one database as no one database contains all of the information available on any given topic.

Are your results useful?
Searchers must consider the quality of results that they find to be sure that they are adequate. Are you finding relevant results? If your results do not seem to match your search question, reconsider the search strategy.

Did you format your search query appropriately for the specific database
Databases may return odd results because they are confused by the search query. Remember to capitalize Boolean search connectors (AND, OR, NOT) if necessary and take advantage of other search features in the particular database. See the Help and Tutorial sections of each database that you search for assistance.

Report your results

According to 9 CFR 2.31 (d)(1)(ii) of the Animal Welfare Act, the principal investigator is required to provide a written narrative to the IACUC stating that alternatives to painful procedures have been explored and the results of that search.

Animal Care Policy #12 of the USDA Animal Care Resource Guide, “Written Narrative for Alternatives to Painful Procedures” states:

When a database search is the primary means of meeting this requirement, the narrative must, as a minimum, include:

  1. the names of the databases searched;
  2. the date the search was performed;
  3. the period covered by the search; and
  4. the key words and/or the search strategy used.

Regardless of the alternatives source(s) used, the written narrative should include adequate information for the IACUC to assess that a reasonable and good faith effort was made to determine the availability of alternatives or alternative methods. 

It will help your report to keep a log of the above four points for each search performed. You will be required to report this information anew to the IACUC when submitting a new protocol, amending an existing one, or requesting renewal.

Explanations of why an identified alternative was not used in the experimental procedure (if one is available) must also be included in the appropriate fields in your IACUC applications, as stated above.

In some fields, the development of new procedures in research may not be reported in journal literature, and thus may not be indexed in databases such as PubMed/MEDLINE. In these cases, it is the responsibility of the principal investigator to ensure that a search of appropriate literature sources such as government reports and conference proceedings is performed.

When an expert is consulted, a description of his/her credentials and relevant expertise must be included.

Manage your results

Keeping track of what databases you have searched, what keywords and questions you used in each database, and the results from each search can be time-consuming. Using citation managers like EndNote, RefWorks, Mendeley, and Zotero has some major advantages. One is that you can attach notes to each reference, including keywords, subjects, and abstracts; this can help you to document your alternatives search. You can also automatically remove duplicate references that you have retrieved from searching different databases.