Fourteen patients with mania unresponsive to lithium were treated with verapamil in an open study. None of the eight patients treated for acute episodes of mania or hypomania showed improvement, although four patients experienced dysphoria, with two of the four switching into depression. Four patients were treated with verapamil prophylactically; one showed a mild improvement and one, a clear positive response. Two patients with persistent pharmacological hypomanias tolerated antidepressants and became euthymic while on verapamil. A case of pharmacological hypomania successfully treated with verapamil is presented in detail. A controlled trial using verapamil to prevent pharmacological mania/hypomania is indicated.