Formic acid (CAS 64-18-6) is a strong organic acid with a pungent odor. Most of the formic acid toxicity is from research on methanol as formic acid is a toxic metabolite of methanol. It has replaced inorganic acids in manufacturing and has shown potential use in new energy technology. Formic acid is an inhibitor of the mitochondrial cytochrome oxidase, causing histotoxic hypoxia and acidosis. The acidosis causes e.g., dilatation of cerebral vessels, facilitation of the entry of calcium ions into cells, loss of lysosomal latency, and deranged production of ATP. Therefore, the target organs of formic acid toxicity are high-energy-demanding organs like central nervous system, kidney, and heart.