—The information provided by Drs Méry and Kanfer is a valuable addition to the literature on erythromycin pharmacokinetics in disease states. Steady-state plasma concentration and interpatient variability data are needed before definitive recommendations can be made for erythromycin dosing in the presence of renal insufficiency. A risk-benefit analysis of the severity of the infection v the risk of ototoxicity should be made for each patient. Patient body weight must also be considered in the choice of dose. Based on our knowledge, it seems reasonable to restrict the erythromycin dose to 1 g/day for infections of mild to moderate severity in adults with renal insufficiency. However, larger doses may be needed for the treatment of severe infections, eg, those due to Legionella sp.