We describe seven women who developed acute polyarthritis after prolonged treatment with minocycline for acne. Arthritis persisted until minocycline was withdrawn, then recovered rapidly. A mild elevation of alanine or aspartate transaminase was noted in 4 patients, while pulmonary infiltrates were found in 2 patients. Antinuclear antibodies (ANA) were persistently present throughout treatment in 4 patients, but were only present on one occasion in 2 women and were absent in one. This syndrome has been described as "drug-induced lupus" although, as described with other drugs, many patients do not fulfil the diagnostic criteria for lupus. The proposed criteria for the diagnosis of "drug-induced lupus", which require only one clinical feature of SLE, also require a positive ANA test and therefore might exclude these patients. This could result in failure to recognise minocycline as the cause of the arthritis, and hence lead to prolonged illness and unnecessary investigations and treatment.