Background: Increased oxygen free radical and reduced glutathione level in the eye lens are important risk factor for cataract formation. The antioxidative property and increasing cellular and extra cellular glutathione level have been reported by several herbal medicines including silymarin.

Objective: In present interventional study Silybum marianum L. seed extract (silymarin) was tested against galactose-induced cataract development in rats.

Methods: Thirty male 45 days old wistar rats (150 – 200 g), were divided in three groups of 10 rats each. Cataract was induced in two groups of rats following feeding them with 30% galactose diet for 40 days. One group kept as control and silymarin in the dose of 200 mg/kg/d was administered orally (mixed with galactose diet) to other group for 40 days. Cataract development in the rats lens was observed daily by ophthalmoscope and naked eye during the study. The glutathione (GSH) and lipid peroxides (LPO) levels were determined after 20 days in all rats left eye lens.

Results: The results indicated that, in silymarin treated group all stage of cataract development were significantly delayed as compared to control group. In rats treated with silymarin the lens GSH level was increased significantly (p<0.01) and LPO levels was decreased significantly as compared to control group (p<0.05).