Small, multiple doses of acetone, cyclohexanone and dimethyl sulfoxide administered either topically or subcutaneously on the backs of guinea pigs over a period of 3 to 8 weeks caused cataracts in 29 out of 120 animals. Lens changes began as early as 8 weeks and as late as 6 months. They consisted of subcapsular focal or extensive vacuolated areas extending from the periphery towards the center of the lens. The histological appearance of the lenses was similar to that of senile cataracts and some forms of diabetic cataracts.