SHEET /m/propionic-acid · PubChem CID 1032 · CAS 79-09-4 · REV 2026.07
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Propionic acid
from sourceC3H6O2 · 74.08 g/mol
PA · carboxyethane · pseudoacetic acid · metacetonic acid
What is Propionic acid?
The mold inhibitor in packaged bread, and one of the short-chain fatty acids your gut bacteria make from fiber. from source
CategoryFood & flavor
Chemical familyCarboxylic Acids
Fig. 1 · 2D structure RDKit
SMILES
CCC(=O)OThe dose makes the poison inferred
A reported rat oral LD50 for Propionic acid is 2,600 mg/kg, the dose lethal to half the animals tested. Scaled by body mass alone:
182.0 g
a median lethal dose scaled to 154 lb (182,000 mg)
“The dose makes the poison” is a cross-species estimate shown as neutral science, not a threshold anyone should act on. Real toxicity depends on the person, not body mass alone.
Toxicity & hazards
Toxicity · LD50
2,600 mg/kg · very low toxicity · LD50 rat oral from source
The dose lens above scales this to a body weight.
2 more reported values
- 625 mg/kgLD50 · iv · mouse
- 3,500 mg/kgLD50 · other · rat
DangerFlammableCorrosiveToxicIrritantH226, H302, H303, H311, H314, H318, H335, H402from source
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Where Propionic acid leads
Relatedcomputed
Butyric acid53% similarBoth carry a carboxylic acid group.Propionate50% similarValeric acid47% similarBoth carry a carboxylic acid group.Succinic acid46% similarBoth carry a carboxylic acid group.Glycolic acid46% similarBoth carry a carboxylic acid group.Glycine43% similarBoth carry a carboxylic acid group.