Tea, considered astringent, stimulant, and acts as a nervine or nerve sedative, frequently relieving headaches. It may also cause unpleasant nerve and digestive disturbances. The infusion is also recommended for neuralgic headaches. According to Leung, tea is reportedly effective in clinical treatment of amebic dysentery, bacterial dysentery, gastroenteritis, and hepatitis. Teabags have been poulticed onto baggy or tired eyes, compressed onto headache, or used to bathe sunburn.
Leaves also contain carotene, riboflavin, nicotinic acid, pantothenic acid and ascorbic acid.
Ascorbic acid, present in the fresh leaf, is destroyed in making black tea. Malic and oxatic acids occur, along with kaempferol, quercitrin, theophylline, theobromine, xanthine, hypoxanthine, adenine, gums, dextrins, and inositol. More properly it only indicates that Camellia has been more intensively studied than most herb teas. According to Tyler, there is evidence indicating that the condensed catechin tannin of tea is linked to high rates of esophageal cancer in some areas where tea is heavily consumed. This effect apparently may be overcome by adding milk which binds the tannin preventing its deleterious effects.