Clonidine efficacy was evaluated in 24 manic inpatients, hospitalised in a locked ward. This is a double blind and randomized study. The duration of the trial was 14 days, and the daily dose of clonidine was 0.225 mg/day during the first week, increased to 0.450 mg/day during the second week, in the case of incomplete improvement. There was a trend for a better efficacy of clonidine over placebo, but this did not reach significant, due to an important amelioration of many patients under placebo. The effects of the hospitalisation in a locked ward are discussed.