Peritoneal dialysis has become an accepted treatment modality for end-stage renal disease. The introduction of continuous ambulatory peritoneal dialysis (CAPD) has further popularised this technique. The need for adjustment of drug dosage in patients with endstage renal disease and the need for supplemental dosages following haemodialysis are well recognised. Little documentation exists concerning the need for supplemental drug dosage in patients on peritoneal dialysis. Knowledge of the influence of peritoneal dialysis on the elimination of specific drugs is essential to the rational design of dosage regimens in patients undergoing this dialysis technique.This review addresses the clinical pharmacokinetic aspects of drug therapy in patients undergoing peritoneal dialysis and considers: (1) the efficiency of the peritoneal membrane as a dialysing membrane; (2) the effects of peritoneal dialysis on the pharmacokinetics of drugs; (3) the pharmacokinetic models and estimation methods for peritoneal dialysis clearance and the effects of peritoneal dialysis on drug elimination; (4) the influence of the pharmacokinetic parameters of drugs on drug dialysability; and (5) the application of pharmacokinetic principles to the adjustment of drug dosage regimens in peritoneal dialysis patients. Data on drugs which have been studied in peritoneal dialysis are tabulated with inclusion of pharmacokinetic and dialysability information.