From 1974 to 1989, 37,392 patients were admitted to the divisions of general internal medicine of the CHDM hospitals. 19,082 of them were treated with a minor analgesic or an NSAID. In 95 of the exposed patients, an allergic or a pseudoallergic reaction to one or two of these drugs was observed. From 1981 to 1990, general practitioners, hospitals and the pharmaceutical industry reported to SANZ 158 individual cases with comparable reactions to 175 exposures of the same kind. Of the 15 different syndromes and symptoms registered in both institutions, most were reactions of the skin, mainly the usual maculopapular exanthemas (rash), urticaria and angioedema. In the CHDM, allergic or pseudoallergic reactions were observed in 0.23% of patients exposed to minor analgesics (including ASA preparations on a daily dose up to 1.0 g and pyrazolones, mainly metamizole, propyphenazone) and in 0.81% of patients exposed to NSAIDs (including the pyrazolone oxyphenbutazone). In the experience of the Comprehensive Hospital Drug Monitoring in Berne and St. Gallen (CHDM) and the Spontaneous Adverse Drug Reactions Center of Switzerland (SANZ).