1 During the three years 1978--1980 the Swedish Poison Information Centre received reports of 184 patients hospitalized due to beta-adrenoceptor blocker overdosage. Of the 35 patients who developed signs of severe cardiac dysfunction (HR less than 50 beats/min, systolic blood pressure less than 80 mm Hg), 23 had ingested propranolol, 10 metoprolol and 2 alprenolol. 2 The mean value of the defined daily doses (DDD) per 1000 inhabitants per day in Sweden during these years were 11.97 for propranolol, 8.02 for alprenolol and 7.74 for metoprolol. The incidence of severe poisoning due to alprenolol overdosage is lower than expected according to DDD. 3 During 1979 19 persons died from overdosage with beta-adrenoceptor blockers in Sweden: 15 due to propranolol (non-selective, lacks intrinsic sympathomimetic activity), 2 to metoprolol (cardioselective, lacks intrinsic sympathomimetic activity). These findings indicate that severe and even fatal poisoning may occur regardless of the type of beta-blocking agent. 4 The usefulness of prenalterol, a cardioselective beta-adrenoceptor partial agonist, in reversing unwanted cardiac effects of beta-adrenoceptor blocking agents is illustrated by two cases of massive propranolol intoxication (maximal plasma concentrations of propranolol 7.2 and 7.8 mumol/l respectively). Prenalterol in high doses (130 and 280 mg/24 h respectively) restored cardiac function.