How toxic is Formic acid?

The reported LD50 of Formic acid is 700 mg/kg (mouse, oral). An LD50 is an animal study measurement, not a dose for a person. Its GHS hazard label carries the signal word Danger and the hazard pictograms Flammable, Corrosive, Toxic and Irritant.

What kind of molecule is Formic acid?

Formic acid has the formula CH2O2 and a molecular weight of 46.025 g/mol. MoleculeFinder files it under organic acids, in the everyday chemistry group.

Formic acid

CH2O246.025 g/mol Calculated

Also called hydrogen carboxylic acid, aminic acid, methanoic acid and methoic acid.

The acid an ant injects when it bites, and the sting of a nettle. Industrially it is a descaler and a preservative in animal feed.

Sources and notes

The introductionfrom sourceMoleculeFinder curated
Other namesfrom sourceWikidataIts English label and aliases on Wikidata.
Formula and weightcomputedPubChem
2D drawingcomputedPubChem structure, drawn by RDKit
3D modelfrom sourcePubChem 3D conformerLoaded after the page has painted, and on a phone only when you ask for it; the 2D drawing shows until it arrives.

Properties and sources

Calculated by PubChem

Molecular formula: CH2O2
Molecular weight: 46.025 g/mol
XLogP3octanol/water, log units: −0.2
Polar surface areatopological: 37.3 Å²
H-bond donors: 1
H-bond acceptors: 2
Rotatable bonds: 0
Complexity: 10

Measured LD50, HSDB via PubChem

700 mg/kg pure formic acid, mouse, oral

An LD50 is an animal study measurement, not a dose for a person.

Reported Hazard label (GHS), ECHA, EU CLP Regulation, Safe Work Australia via PubChem

Danger Flammable pictogram (GHS02), Corrosive pictogram (GHS05), Toxic pictogram (GHS06) and Irritant pictogram (GHS07); hazard statements H226, H290, H302, H314, H318, H331, H335

Groups it belongs to

Category: Everyday chemistry
Family: Organic acids
Chemical groups: Carboxylic Acids, Aldehydes
Hazard classes: Flammable, Corrosive, Acutely toxic, Irritant, GHS Danger
Size: Under 100 g/mol

SMILESC(=O)O

PubChem CID 284 · Wikidata Q161233 · InChIKey BDAGIHXWWSANSR-UHFFFAOYSA-N · Data refreshed 2026-11-09

How MoleculeFinder sources and labels its data

Questions

What is Formic acid?: The acid an ant injects when it bites, and the sting of a nettle. Industrially it is a descaler and a preservative in animal feed.
How toxic is Formic acid?: The reported LD50 of Formic acid is 700 mg/kg (mouse, oral). An LD50 is an animal study measurement, not a dose for a person. Its GHS hazard label carries the signal word Danger and the hazard pictograms Flammable, Corrosive, Toxic and Irritant. from sourcefrom source
What kind of molecule is Formic acid?: Formic acid has the formula CH2O2 and a molecular weight of 46.025 g/mol. MoleculeFinder files it under organic acids, in the everyday chemistry group. from sourcefrom sourcefrom sourcefrom source
What else is Formic acid called?: Formic acid is also called hydrogen carboxylic acid, aminic acid, methanoic acid and methoic acid. from source

Sources and notes

Calculated valuescomputedPubChemComputed from the structure, so no laboratory conditions apply; complexity is PubChem's own structural score.
LD50from sourceHSDB via PubChemOther values the sources report: dog, oral, 4,000 mg/kg; dog, intravenous, 3,000 mg/kg. The page shows the one LD50 the site uses everywhere.
Hazard labelfrom sourceECHA, EU CLP Regulation, Safe Work Australia via PubChemThe label combines these classifications.
ECHAfrom sourceAttributionSource: European Chemicals Agency, echa.europa.eu.
Safe Work Australiafrom sourceAttributionSource: Safe Work Australia, Hazardous Chemical Information System, © Commonwealth of Australia, CC BY 4.0.
Data refreshedfrom sourceMoleculeFinder2026-11-09