In an attempt to improve the low reporting rate of adverse drug reactions (ADR) we examined the potential for hospital nurses to report ADRs through a spontaneous 'yellow card' system. Over 14 months 100 cards were received (compared with 28 cards from doctors). Although reports from doctors for the same period were of a more substantial nature, nurses nevertheless reported many life threatening (17%) or moderately severe (76%) reactions. Nurses identified uncertainty concerning their role and deficient in-service education on drug therapy as major constraints in their participation. Given their unique position in drug administration and recording observations on patients, we believe that nurses could contribute significantly and in a complementary fashion to the spontaneous reporting of adverse reactions.