Gossypol is a polyphenol found in Gossypium that exhibits anti-fertility, antimalarial, immunosuppressive, antiviral, and anticancer chemotherapeutic activities. Gossypol inhibits calcineurin, PKC, and other kinases. Gossypol is under consideration for use as a male contraceptive as it induces spermatogenesis arrest. Gossypol also inactivates HIV-1 in vitro and inhibits viral entry of H5N1 influenza virus. In vitro, gossypol inhibits ConA-induced increases in NF-κB, NFAT, and AP-1 signaling, suppressing T cell activation in vitro. Gossypol also acts as a BH3 mimetic, inhibiting Bcl-2 and Bcl-xl, inducing G2/M phase cell cycle arrest in wild type and B-RAF mutant melanoma and myeloma cells.