After a 16-week clinical trial of a new anti-inflammatory drug, the participants were given a factual test to determine whether they had understood and remembered the information given them when consent was solicited. They filled out a questionnaire about their reasons for volunteering and their views on clinical studies and on medical practice in general. Demographic information was also obtained. Two thirds of the participants did not remember that they had been informed about potential risk (gastrointestinal ulceration). Some subjects remembered, but misunderstood, what they had been told; others developed erroneous ideas about the trial and the study drug. The volunteers agreed to participate in the study to help both their own arthritis and that of other patients. They took pride in their self-sacrifice and in being commended by their friends for their altruism. Analysis of the demographic data shows that indigent persons are not necessarily the most likely to participate in clinical trials. Two thirds of the subjects were from the middle class. The median family income was $13,000. To improve the informed consent procedure, we recommend group meetings in which the participants in a clinical trial can discuss the protocol and the risks of the study. Obtaining consent again, after initial anxiety has decreased, may improve comprehension.