A tannin is an astringent chemical derived from plants. Tannic acid made by China H&Z® factory is one type of tannin that has a fairly weak acidity. In some trees, this chemical may act as protection against pests and fires, and it is believed that humans can benefit from the antibacterial, antifungal, and antioxidant properties of the substance. It is also used for industrial purposes, such as leather production and wood staining.This substance is usually found as a yellow, white, or light brown powder that tends to easily dissolve in water. It generally does not have a smell, but the taste is one that can cause a person to pucker.Since it will cause constipation in humans, tannic acid can be used to treat diarrhea. It can also be used to reduce the swelling of hemorrhoids and control internal bleeding. Externally, tannin can be added to creams and salves to help combat muscle and joint problems and to help heal wounds. It may also be used for the antifungal treatment of the feet, toenails, or fingernails.People are warned not to consume large amounts of tannic acid, and it should not be consumed on a regular basis. Although it can be helpful in many ways, tannin may also have adverse effects.