Now days, research studies have concentrated on complementary (alternate) medicine in treating a large number of infectious and non-infectious diseases, including cancer. The attention of research now shifted towards alternative natural medicine and is being preferred to the toxic effects of the synthetic drugs that are used to treat such diseases. Studies have shown that many natural plant products like amygdalin extracted from apricots and almonds to have shown anticarcinogen effect on many types of cancers including oral cancer. Herein we made an attempt to evaluate the anti-carcinogenic property of Muntingia Calabura proteins against Oral cancer cell lines. Oral cancer cell lines (KB cell line) were used in the present study. The proteins were extracted from Muntingia Calabura roots and the antiproliferative and cytotoxic activity on KB cell line was evaluated using 3-(4,5-dimethylthiazol-2-YL)-2,5-diphenyl tetrazolium bromide assay. The crude proteins of Muntingia Calabura roots showed cytotoxic and anti-proliferative activity on KB cell lines at a maximum efficacy at 100 μg/Ml is about 58% and maximum IC50 value is 52 μg/Ml. The crude proteins of Muntingia Calabura roots effective as an antiproliferative agent, who caused apoptosis in oral cancer cell line.