Brassica juncea is a polyphenols enriched edible plant, with diverse medicinal uses of different parts of which have been mentioned in the Ayurveda. The effects of 10 daily oral doses (100, 200, and 400 mg/kg/day) of a methanolic Brassica juncea leaf extract in rat models of anxiety using nondiabetic and alloxan-diabetic rats were quantified. In all the three behavioural tests used, i.e. elevated plus maze, open field, and social interaction tests, anxiolytic-like activity of the extract was observed in the diabetic animals only. Quantitatively, the efficacy of the highest tested dose of the extract in these tests was always less than those observed after its lower ones. These observations provide further experimental evidences for the conviction that Brassica vegetables could as well be useful for combating diabetes associated mental health problems.