Skip Navigation



We owe much to laboratory animals, and that debt can best be repaid by good treatment and keeping painful experiments to a minimum.
—former U.S. Senator Bob Dole*

Minimizing Pain and Distress for Laboratory Animals

Refinement is the third of the "Three R's" of alternatives, first formulated by British researchers William Russell and Rex Burch in their classic 1959 book, The Principles of Humane Experimental Technique. They defined refinement as follows: "any decrease in the incidence or severity of inhumane procedures applied to those animals which still have to be used." In recent years, we have come to speak of refinement more in terms of techniques that minimize any pain or distress the animals may experience.

Refinement covers anything that serves to reduce the animals' pain and distress or to enhance their well-being. These alternatives may come in a great variety of forms. Giving an animal appropriate medication for pain is a prime example. Techniques that are less invasive to the animal also may constitute refinement. For example, researchers can use such modern medical technologies as ultrasound or Magnetic Resonance Imaging (MRI) to look at what is happening inside an animal without cutting into it. Refinement also includes giving animals bigger cages, offering them appropriate toys to play with, and allowing them to have companions of their own kind (if that is a natural condition for the species).

This refinement section follows a format similar to that of the Altweb special section on monoclonal antibodies, or MABs, with introductory text explaining the topic in non-technical language, accompanied by a set of links to relevant databases, web sites, books, articles, abstracts, and so on. The section addresses the following topics:

This refinement section was developed for Altweb by Dr. Roberta Friedman, in cooperation with CAAT's communications coordinator. Dr. Friedman holds a doctorate in pharmacology and has more than 20 years experience as a science writer.

We plan to continue developing and expanding this section. If you have any additions or corrections to offer, please e-mail

* Senator Dole helped bring about the 1985 amendment to the U.S. Animal Welfare Act, which added many features aimed at reducing pain and distress for laboratory animals.

General Readings and Resources on Refinement

New ALTEX:1/2018

ALTEX cover 1/2018

Support ALTWEB, Make a Gift
Online Humane Science Course


Building a Better Epithelium: Breaking the Barrier to the Next Generation of Toxicity Testing
March 10, 2018
San Antonio, TX

SOT Satellite Meeting: Updates on Activities Related to 21st Century Toxicology and Related Efforts: Invited Presentations and Open Mic
March 15, 2018
San Antonio, TX

Social Housing Workshop
June 4-5, 2018
Beltsville, MD

2nd Pan-American Conference for Alternative Methods
August 23-24, 2018
Rio de Janeiro, Brazil 

Eurotox 2018
September 2-5, 2018
Brussels, Belgium

20th International Congress on In Vitro Toxicology (ESTIV2018)
October 15-18, 2018

More Meetings...