Tannin
![Tannic acid, a type of tannin](/Images/godic/202501/17/Tannic_acid2845.png")
![A bottle of tannic acid solution in water.](/Images/godic/202501/17/Bottle_of_tannic_acid2848.jpg")
![Tannin powder (mixture of compounds).](/Images/godic/202501/17/Tannin_heap2854.jpeg")
![](/Images/godic/202501/17/Gallic_acid.svg2901.png")
A tannin (also known as vegetable tannin, natural organic tannins, or sometimes tannoid, i.e. a type of biomolecule, as opposed to modern synthetic tannin) is an astringent, plant polyphenolic compound that binds to and precipitates proteins and various other organic compounds including amino acids and alkaloids.