Objective: Cancer remains one of the most dreaded diseases causing an astonishingly high death rate. Despite the use of surgical resection and aggressive chemotherapy, nearly 50% of patients with carcinoma develop recurrent disease, highlighting the need for improved therapies. Henceforth, complementary and alternative medicine is slowly emerging as an option. A variety of ingredients of traditional medicines and herbs are being widely investigated in several parts of the world to analyze their potential as therapeutic agents against cancer. In the present study we investigated the efficacy of methanol extracts of Canthium dicoccum, for its clonogenic inhibition on Human Breast cancer (MD-MB-231), Prostate cancer (PC-3) and Lung cancer (Calu-6) cell lines. Methods: The cytotoxic effect of methanolic extract of Canthium dicoccum was evaluated by MTT assay on MD-MB-231, Calu-6, and PC-3 cells. Results: The methanol extract of C. dicoccum showed significant cytotoxicity against MD-MB-231and Calu-6, when compared to PC-3 cells. Conclusion: The methanol extracts of C. dicoccum showed effective cytotoxic activities in a dose and time dependent manner. Future work will be interesting to know the chemical composition and also better understanding the mechanism of action will help in developing it as drug for therapeutic application.