Measurement of side effects of drugs.

In a clinical trial of two antirheumatic agents two methods of collection of side effects were used, one with and the other without a check list of possible symptoms. Findings suggested that the use of a check list interfered with the collection of side effects. Known side effects of aspirin-tinnitus, deafness, and gastrointestinal disturbance-were more efficiently shown and symptoms not included in the check list were more likely to be reported when a check list was not used.