It is an isomer of cresotinic acid (2-hydroxy-3-methylbenzoic acid) and oxymethylbenzoic acid (2-methoxybenzoic acid).

Propionic acid (PA) is widely used as an antifungal agent in food. It is present naturally at low levels in dairy products and occurs ubiquitously together with other short-chain fatty acids (SCFA) in the gastro-intestinal tract of humans and other mammals as an end-product of the microbial digestion of carbohydrates.

5'-Guanylic acid is involved in several metabolic disorders, including AICA-ribosiduria pathway, ?adenosine deaminase deficiency,adenine phosphoribosyltransferase deficiency (aprt), and the 2-hydroxyglutric aciduria pathway.