The principal use of formic acid is as a preservative and antibacterial agent in livestock feed. When sprayed on fresh hay or other silage, it arrests certain decay processes and causes the feed to retain its nutritive value longer, and so it is widely used to preserve winter feed for cattle. In the poultry industry, it is sometimes added to feed to kill salmonella bacteria. Other uses:

It is used to process organic latex (sap) into raw rubber.
Beekeepers use formic acid as a miticide against the Tracheal (Acarapis woodi) mite and the Varroa mite.
It is of minor importance in the textile industry and for the tanning of leather.
Some formate esters are artificial flavorings or perfumes.
It is the active ingredient in some brands of household limescale remover.
It is used in laboratories as a solvent modifier for HPLC separations of proteins and peptides, especially when the sample is being prepared for mass spectrometry analysis.
It is used by clinical pathology laboratories to disinfect prion activity in brain samples
In synthetic organic chemistry, formic acid is often used as a source of hydride ion. The Eschweiler-Clarke reaction and the Leuckart-Wallach reaction are examples of this application. It is also used as a source of hydrogen in transfer hydrogenation.

In the laboratory formic acid is also used as source for carbon monoxide, which is set free by the addition of sulfuric acid. Formic acid is also a source for a formal group for example in the formylation of methylaniline to N-methylformanilide in toluene.[2]

Fuel cells that use modified formic acid are promising.