Uses As A Medication
Tannic acid was once used as a treatment for many toxic substances, such as strychnine, mushroom, and ptomaine poisonings in the late 19th and early 20th centuries.
The introduction of tannic acid treatment of severe burn injuries in the 1920s significantly reduced mortality rates During World War I, tannic acid dressings were prescribed to treat "burns, whether caused by incendiary bombs, mustard gas or lewisite... Where tannic acid is not available, strong, lukewarm tea is a good substitute." After the war this use was abandoned due to the development of more modern treatment regimens.
Today tannic acid is still used in pharmaceutical applications to produce albumine tannate which is used as an anti-diarrhea agent. Tannic acid is also used to produce tannate salts of certain anti-histamins and anti-tussives to impart increased stability or slow release properties to the API (active pharmaceutical ingredient).
In a systematic review by Chung et al. (1998) they found that Tannins have also been reported to exert many physiological effects, such as to accelerate blood clotting, reduce blood pressure, decrease the serum lipid level, produce liver necrosis, and modulate immunoresponses. This would explain common folklore such as that soaking feet in tannic acid (or strong tea) can treat or prevent blisters; foot odor; and rough, dry feet. A further example is that "A popular home remedy to stop the bleeding after wisdom tooth extraction is applying tea bags in the back of the jaws and biting down, given that the tannic acid in tea helps to clot blood."
Tannic acid glycerite is used for local application.
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