Buchanania lanzan is a widely used plant with a long history of traditional medicinal use for the treatment of various diseases. The present study is aimed at evaluating the adaptogenic activity of the methanolic extract of Buchanania lanzan leaves using the swim endurance model in all groups under normal and stressed conditions. Urinary vanillylmandelic acid (VMA) and ascorbic acid were selected as non-invasive biomarkers to evaluate the antistress activity. The 24 h urinary excretion of vanillylmandelic acid (VMA) and ascorbic acid were determined by spectrophotometric methods. Daily administration of the extract at doses of 10,20,30,40 and 50 mg/kg body weight prior to induction of stress inhibited stress-induced urinary biochemical changes in a dose-dependent manner without altering the levels in normal control groups. The methanolic extract exhibited significant anti-stress activity.