Gyromitrin is a potent inhibitor of tumor growth and apoptosis in human cancer cells. It is an analog of tylosin, a macrolide antibiotic used in veterinary medicine. Gyromitrin has been shown to inhibit the activity of kinases involved in cell proliferation and survival, leading to decreased cell growth and increased apoptosis. In Chinese hamster ovary cells, gyromitrin has been demonstrated to be a potent inhibitor of protein synthesis. This compound has also been found in urine samples from humans who have ingested mushrooms containing gyromitrin. Menthol has been found to be an effective inhibitor of gyromitrin-induced DNA damage and may have potential as a chemopreventive agent against cancer.