The present study was aimed to evaluate the therapeutic effects of Withania somnifera along with paclitaxel on lung tumor induced by benzo(a)pyrene in male Swiss albino mice. The levels of ATPase enzymes and lipid peroxidation were evaluated in lung cancer bearing mice, in erythrocyte membrane and tissues. The extent of peroxidation was estimated by measuring the thiobarbituric acid-reactive substances. Simultaneously the activities of different ATPases (Na(+)/K(+)-ATPases, Mg(2+)-ATPases and Ca(2+)-ATPases) were determined. The alterations of these enzyme activities in membrane and tissues were indicative of the tumor formation caused by benzo(a)pyrene (50 mg/kg body weight, orally) in cancer bearing animals. The activities of these enzymes were reversed to near normal control values in animals treated with Withania somnifera (400 mg/kg b.wt, orally) along with paclitaxel (33 mg/kg b.wt, i.p). Treatment with Withania somnifera along with paclitaxel altered these damage mediated through free radicals, and the treatment displays the protective role of these drugs by inhibiting free radical mediated cellular damages. Over, based on the data providing a correlation Withania somnifera along with paclitaxel provide stabilization of membrane bound enzyme profiles and decreased lipid peroxidation against benzo(a)pyrene induced lung cancer in mice.