Abstract: Medicinal plants are part and parcel of human society to combat diseases, from the dawn of civilization. There exists a plethora of knowledge, information and benefits of herbal drugs in our ancient literature of Ayurvedic, Siddha, Unani and Chinese medicine. Aloe vera (L.) is commonly used plant for burn, cosmetic etc.. It belongs to the family Liliaceae. The present study reports antitumour activity of this plant in two stage skin carcinogenesis tumour model and antimutagenic activity using chromosomal aberration assay in the experimental animals. In present investigation, the comparative antitumour effect of Aloe vera extract has been undertaken by topical/oral application of 7, 12-dimethyabenz (a) anthracene followed by 1% croton oil till the end of the experiment (16 weeks).GSH level were also measured during carcinogenicity studies. In another set of experiment the antimutagenicity activity was performed using chromosomal aberration assay in bone marrow cells of Swiss albino mice. The results have indicated that there was a delayed in the first appearance of tumour and significant reduction in incidence and cumulative numbers of papillomas which were observed in the Aloe vera extract treated groups (by topical and oral route) as compared to control. The GSH levels were restored in Aloe vera extracts along with DMBA + croton oil treated groups whereas DMBA + croton oil treated group depleted the GSH levels. In chromosomal aberrations assay, single application of Aloe vera extract at the dose of 250, 500, and 750 mg/kg b.wt.,24 hours prior the i.p. administration of Cyclophosphamide (at the dose of 50 mg/kg) have significantly prevented the chromosomal aberrations in bone marrow cells of mice as compared to Cyclophosphamide group. The above studies indicate that Aloe vera may be used as an alternative medicine for chemoprevention of cancer. Therefore, the present study is immensely important in future drug development programs for the cancer trea