Male infertility due to sulphasalazine.

Four young immigrants whose ulcerative colitis was controlled by sulphasalazine had oligospermia and infertility. No other cause for infertility was found in any of them nor in their wives. Findings on semen analyses rapidly improved in all patients on withdrawal of sulphasalazine, which resulted in four pregnancies in three of the wives. Reintroduction of sulphasalazine was followed by rapid deterioration in the semen of two patients. The frequency and importance of the effect of sulphasalazine on fertility requires further evaluation.