Abstract: The invention relates to aqueous suspension of dried latex (DL) of Calotropis procera and to a method of preparation for the prevention/treatment of cancer. The DL suspension when administered orally in the X-myc mice—a transgenic mouse model of hepatocellular carcinoma (HCC), was effective in protecting the animals from the atypical mitosis and displastic/neoplastic changes occurring in vivo. Further, the DL suspension did not show any observable side effects when administered orally to the animals for 16 weeks. Further, the purified fractions of the latex were found to exhibit potent cytotoxic activity in in vitro cell culture system using two different cancer cell lines.