A programme of antiepileptic treatment in a rural and semi-urban region in Kenya was assessed. Patients with generalised tonic-clonic seizures were treated according to one of two simple drug protocols. Health workers screened cases reported by key informants in the community. From the 529 patients identified by health workers as having active seizures 302 patients aged 6-65 years were recruited by a psychiatrist for therapy with carbamazepine or phenobarbitone. Treatment was supervised largely by primary health workers, and the programme was monitored by a research team, which assessed the effectiveness of treatment. Of the 249 patients who completed the study, 53% became seizure-free in the second 6 months of therapy, and another 26% had substantially (50% or more reduction) fewer seizures than in the 6 months before therapy. The similarity of these findings to those obtained in newly diagnosed patients in the developed world, the low drop-out rate, the low rate of withdrawal due to adverse effects, and the acceptable compliance with therapy indicate that health workers can monitor therapy adequately. Most patients had had several years of delay before starting therapy for their epilepsy, yet they responded well--a finding that does not support the suggestion that the disorder becomes intractable if not treated early.