... a trihydroxybenzoic acid, a type of phenolic acid, a type of organic acid, also known as 3,4,5-trihydroxybenzoic acid, found in gallnuts, sumac ... its name, it does not contain gallium.Gallic acid is commonly used in the pharmaceutical industry.It is used as a ... analytes by the Folin-Ciocalteau assay; results are reported in gallic acid equivalents.Gallic acid can also be used as a starting material ...