According to the National Institutes of Health Office of Laboratory Animal Welfare, researchers must try to minimize distress in animals whenever possible: "Animals used in research and testing may experience pain from induced diseases, procedures, and toxicity. The Public Health Service (PHS) Policy and Animal Welfare Regulations (AWRs) state that procedures that cause more than momentary or slight pain or distress should be performed with appropriate sedation, analgesia, or anesthesia.
