In a single-dose study the analgesic activity of 400 mg doxpicomine was compared with 4 and 8 mg morphine administered intramuscularly. Our subjects wee 43 men with moderate or severe postsurgical pain on the first postoperative day. Results of a double-blind trial indicate the analgesic activity of 400 mg intramuscular doxpicomine to be within the range of 8 mg morphine. There was no statistical significance between the effects of 400 mg doxpicomine and 8 mg morphine with the exception of half-hour data where doxpicomine was more effective than morphine. Doxpicomine has a rapid onset of analgesic action, the duration of which is equivalent to that of 8 mg morphine.