Succinic acid is an alpha,-dicarboxylic acid resulting from the formal oxidation of each of the terminal methyl groups of butane to the corresponding carboxy group. It is an intermediate metabolite in the citric acid cycle. It has a role as a micronutrient, an anti-ulcer drug, a nutraceutical, a radiation protective agent and a fundamental metabolite. It is an alpha,omega-dicarboxylic acid and a C4-dicarboxylic acid. It is a conjugate acid of a succinate(1-). Succinic acid is a crystalline organic acid which occurs in living tissue as an intermediate in glucose metabolism.

Pseudoaspidin is a product from Agrimonia pilosa Ledob.