The present study was aimed to detect the CNS depressant activity of the methanol extract of Laurencia papillosa (Forssakal) Greville collected from Kanyakumari coast, Tamil Nadu, India on albino rats. Chlorpromazine (3mg/kg) was used as standard drug. The CNS depressant activity of Laurencia papillosa (Forssakal) Greville was predicted by hole cross test on albino rats. The various methanol extract doses used were 200mg/kg and 400mg/kg body weight of rats. 400mg/kg methanol extract of Laurencia papillosa (Forssakal) Greville showed significant decrease in the movement of rats while 200mg/kg methanol extract showed less effect. 400mg/kg methanol extract exhibited closely significant (p<0.05) decrease in elevated movement as compared to standard drug. From the study it was concluded that the methanol crude extract of Laurencia papillosa (Forssakal) Greville can be used for CNS depressant activity.
