Two patients were hospitalized in moderately deep coma after ingestion of large doses of diazepam with suicidal intent. Three other patients required unusually high diazepam doses for therapeutic reasons (acute alcohol withdrawal, severe tetanus). In all patients, plasma levels of diazepam and its main active metabolite, desmethyl-diazepam, could be determined. The elimination of both substances seems to be dose-independent. Rapid clinical recovery after high diazepam doses is not attributable to rapid elimination of active compounds from the body, but more likely to adaptation or tolerance to their depressant effects. On the other hand, prolonged coma after long-term therapy with high doses is possible.