Phenobarbital, butabarbital sodium, acetylcarbromal, glutethimide, meprobamate and prochlorperazine were evaluated under conditions of clinical practice to determine their relative effectiveness in producing daytime sedation, nighttime hypnosis by multiple daytime dosages, and combined daytime sedation and nighttime hypnosis. A therapeutic index (per cent effectiveness: per cent untoward reactions) was established for each drug. Butabarbital sodium provided the highest rating of sedatives studied for control of anxiety and insomnia by daytime dosages.