Interferons are a family species-specific proteins synthesized by eukaryotic cells in response to viruses and a variety of natural and synthetic stimuli. There are several different interferons commonly used as therapeutics, termed alpha, beta, and gamma. These peptides are used to treat hairy cell leukemia, AIDS-related Kaposi's sarcoma, laryngeal papillomatosis, genital warts, and chronic granulomatous disease. Side effects include black tarry stools, blood in the urine, confusion, and loss of balance.