We report a case of erythema nodosum caused by omeprazoIe. This side e
ffect of omeprazole has not been previously reported, A 35-year-old wh
ite woman developed multiple tender erythematous nodules over the ante
rior aspect of her upper and lower extremities, fever, malaise, and ed
ema, Her symptoms resolved with withdrawal of all preexisting medicati
ons and conservative treatment Her symptoms flared soon after a rechal
lenge with omeprazole. A thorough history, physical examination,, labo
ratory evaluation, and roentgenogram failed to reveal another cause fo
r erythema nodosum, It is clear from the rechallenge that this patient
's erythema nodosum was caused by omeprazole. We consider that omepraz
ole should be added to the list of medications known to cause erythema
nodosum.