: Guidance on the use of clinical signs as humane endpoints for experimental animals used in safety evaluation [77] have been reviewed elsewhere and the reader is advised to look it up. In particular paragraph 62 of the guideline thereof, should always be followed. This paragraph states that “In studies involving repeated dosing, when an animal shows clinical signs that are progressive, leading to further deterioration in condition, an informed decision as to whether or not to humanely kill the animal should be made. The decision should include consideration as to the value of the information to be gained from the continued maintenance of that animal on study relative to its overall condition. If a decision is made to leave the animal on test, the frequency of observations should be increased, as needed. It may also be possible, without adversely affecting the purpose of the test, to temporarily stop dosing if it will relieve the pain or distress, or reduce the test dose.”