Toloxychlorinol is a sedative agent. It is more pleasant alternative to chloral. Toloxychlorinol had low toxicity in the mouse, rat and guinea pig. Large doses of toloxychlorinol induced hypnosis rapidly. The duration of action was intermediate between that induced by moderate-, and long-acting barbiturates. Small doses, insufficient to cause outward signs of depression, significantly prolonged the period of sleep induced by hexobarbital. Toloxychlorinol antagonized convulsions induced by pentylenetetrazole. It displayed no analgesic activity. Pentylenetetrazole completely antagonized the effects of overdosage with toloxychlorinol.