Cigarette smoking is reported to increase the risk of cataract. Likewise, the use of smoky cooking fuel is implicated in the etiology of cataract. In an effort to understand the cellular and molecular basis, the in vitro and in vivo cataractogenetic effects of these smoke condensates have been studied using isolated rat lenses and pigmented rats. Isolated capsulated rat lenses are incubated with cigarette smoke condensate (CSC) and firewood smoke condensate (FSC) for varying periods, with and without antioxidants, in the presence and absence of light. CSC and FSC permeate the lens capsule, impart colour and opacify the lens in a light- and dose-dependent manner. Antioxidants offer partial inhibition against the above damage. The condensates contain polycyclic aromatics which generate reactive oxygen species such as O2 photodynamically, and ppb levels of Fenton metal ions which induce oxidative reactions through .OH. Smoke induced damage possibly occurs through systemic absorption and transport of toxic components to several tissues, and specially into the lens, wherein the turnover is slow, leading to chronic accumulation causing oxidative damage to the constituent molecules and to consequent lenticular opacity.