A fermented soybean-derived phytochemical beverage with potential antineoplastic activity. Fermented soybean protein beverage is reported to exhibit immunostimulatory, anti-viral, pro-apoptotic, anti-angiogenic, anti-proliferative, and anti-inflammatory activities and to enhance the cytotoxic effects of natural killer (NK) cells. The fermentation process is reported to hydrolyze many soybean proteins into amino acids and nitrogen-rich compounds and to protect and enhance the activities of isoflavones such as genistein, protease inhibitors, saponins, phytosterols, inositol hexaphosphate, and other beneficial dietary nutrients and micronutrients found in soybeans. Check for active clinical trialsusing this agent.