Although catechins found in the tea plant are generally considered non-toxic in mice and rats, studies have reported cases of erythema and papular lesions on the skin, conjunctivitis, scleritis, chemosis, discharge, enlarged colon, hemorrhagic fluid in the small intestine, toxicity, hepatic necrosis, skin tumors, and glutathione S-transferase placental form carcinogenesis in the liver [58,76,77,78,79,80]. The gene discussed is HPGDS; the disease is scleritis.