In a double-blind randomized study 47 patients received tofizopam 100 mg orally the night before operation, and 100 mg on the morning of operation; 49 patients received nitrazepam 5 mg and 50 patients received placebo. On average the nitrazepam group slept better and were better sedated than the tofizopam or placebo groups. Compared with placebo or nitrazepam, tofizopam decreased the excitement of the patients. The effect tofizopam on apprehension and excitement was significantly better than those of placebo or nitrazepam. Nitrazepam, but not tofizopam, significantly decreased the induction requirements of thiopentone.