1 A randomised clinical trial was carried out to assess the effects of activated charcoal in the management of suspected tricyclic antidepressant poisoning. 2 Forty-eight patients entered the study, twenty receiving supportive care plus activated charcoal (10 g) and twenty-eight supportive care alone. 3 Drug screening showed that only seventeen patients had taken tricyclic antidepressants alone. 4 Activated charcoal had no effect on either the rate of lightening of coma or the fall in plasma antidepressant concentration in the 'pure' tricyclic antidepressant poisoning group. 5 No serious side-effects of activated charcoal were reported.