Formic acid (HCOOH) was initially detected in the interstellar medium in 1971 by Zuckerman et al., with a second line reported by Winnewisser and Churchwell. It was observed in comet Hale-Bopp and has also been found in chondritic meteorites. It was recently identified in several hot star-forming regions.

Formic acid is the smallest carboxylic acid, which include a carbonyl doubly-bonded oxygen (=O) and a hydroxyl group (-OH) on the same carbon atom. In solution, formic acid may lose the OH proton to yield HCOO-, the formate ion.

The name of a family of ants, Formicidae, reflects their use of formic acid in defense and as a chemical marker.