Leucas aspera (LA), belonging to the family Labiatae, is commonly called as 'chota halkusa'. It grows as a weed on wastelands and roadsides all over India. The plant is used as an insecticide and indicated in traditional medicine for coughs, colds, painful swellings, and chronic skin eruptions. [1] Compounds isolated from the plant include, long-chain aliphatic compounds, a triterpene-leucolactone, sterols-sitosterol, campesterol, stigmasterol and a novel phenolic compound. [2-5] Although LA is an ingredient of polyherbal liver-protective Siddha formulations (Siddhar Hepato capsule-Siddhar Pharma, Chennai, India), it has never been systematically investigated for hepatoprotective activity. Hence, the present study is aimed to evaluate the protective activity of LA in carbon tetrachloride (CCl 4)-induced hepatotoxicity in rats. The herb in full bloom was collected, washed, aerial parts separated, air dried, powdered, and soaked in methanol for 72 h. The extract was then filtered, concentrated under vacuum, and lyophilised to obtain a solid mass (18% w/w). Preliminary phytochemical analysis of the extract revealed the presence of flavonoids, reducing sugars, sterols, alkaloids, saponins, and volatile terpenes. Swiss albino mice were used for toxicity study, while the hepatoprotective study was carried out in adult male Wistar rats (150-200 g). The rats were housed in clean polypropylene cages and fed with commercial rat chow and water ad libitum. Permission was obtained from the institutional animal ethics committee for the study. For acute toxicity study, four groups of two mice each were administered i.p. methanolic extract of LA at 200, 800, 1200 and 2000 mg/kg The animals were continuously observed for 1 h, then frequently for 24 h, and thereafter once per day for 14 days. There was no lethality in any of the groups. One-tenth of the maximum tested dose (i.e., 200 mg/kg, p.o.) of the extract was selected for the evaluation of antihepatotoxic activity. For hepatoprotective study, a total of 30 rats were divided into five groups (n=6 in each group). Group I (vehicle control) and Group II (CCl 4-treated control) were given 5% gum acacia (2 ml/kg, b.w.) p.o for 5 days. Groups III and IV were pretreated with methanolic extract of LA (200 and 400 mg/kg, p.o.; respectively) for 5 days, while Group V was pretreated with silymarin (100 mg/kg, p.o.), a known hepatoprotective agent for 5 days. Liver damage was induced in all groups (except Group I) with 1:1 (v/v) mixture of CCl 4 and olive oil (1 ml/kg, s.c.) injected on days 2 and 3 while olive oil (2 ml/kg, s.c.) was injected to Group I. [6] After 48 h of CCl 4 treatment, that is, on the sixth day, the animals were killed under light ether anesthesia. Blood was withdrawn from the carotid artery, allowed to coagulate at 37 o C for 30 min, serum separated by centrifugation at 2500