Background: Holarrhena pubescens Wall. ex G. Don belongs to the family Apocynaceae and has several therapeutic applications in traditional medicine. This plant has various pharmacological properties such as antihelmintic, antidiuretic and antidiabetic. One of the major concerns, as they are used, is the lack of adequate pharmacological and toxicological data to support their uses. Objective: The present investigation was carried out to evaluate the safety of an ethanolic extract of Holarrhena pubescens Wall.ex.G.Don (Apocynaceae) by determining its potential toxicity after oral administration for 28 days. Methods: In sub-acute toxicity, the extract at the doses of 250, 500 and 1000mg/kg, bw was administered orally for 28 days. After 28 days of treatment, the mice were decapitated; brain was homogenized for evaluating oxidative stress. The brain was fixed in 10 % formalin and processed for histopathological examinations. Phytochemical analysis of the plant extract was performed by (GC-MS). Result: In the sub-acute study in mice, daily oral administration of HP resulted in a significant increase in the lipid peroxidation of treated animals and a decrease in enzymes activity of CAT, SOD, GPX and GR in both, males and females mice. Histopathological analysis showed alterations in the mice brain cortex. From the GC-MS analysis of the plant extract, it was evident that major phytochemicals were present in the ethanol extract of HP. Some major phytochemicals namely, conessimine (17.81 %); lup-20(29)-en-3-one (16.50%); piperidine, 2-(tetrahydro-2-furanyl)-(6.44%); lup-20(29)-ene-3, 28-diol, (3.beta.) (4.82%) and 17- (1, 5-dimethyl-3-phenylsulfanyl-hex-4-enyl (4.37%) were found. Conclusion: H.pubsecne bark ethanol extract was found to be relatively safe in lower doses although at higher doses it can cause lipid peroxidation and damage to the neuronal cell of the brain and should therefore be used with caution.