Erythromycin has a range of activity similar to benzylpenicillin but differs in being predominantly bacteriostatic. The main Indication for its use is in the treatment of streptococcal or pneumococcal infections in patients who are allergic to penicillin. Erythromycin is prescribed in a dosage of 250 mg by mouth every six hours. Jaundice occasionally occurs with erythromycin estolate but it clears on withdrawal of the antibiotic. Allergic reactions to erythromycin are rare but diarrhoea is not uncommon.