Is Borax Toxic?
It depends on how much and how you are exposed. The National Pesticide Information Center says boric acid is low in toxicity if eaten or if it contacts skin, but that in the form of borax it can be corrosive to the eye and irritating to the skin. It says people who ate boric acid had nausea, vomiting, stomach aches and diarrhea, and people who breathed in borax had a dry mouth, nose and throat, with coughing, sore throat, shortness of breath and nose bleeds also reported.
NPIC says products containing boric acid have been registered for use in the United States since 1948, reports that the EPA concluded boric acid is not likely to be carcinogenic to humans, and advises following the first aid instructions on the product label after any exposure and calling the Poison Control Center at 800-222-1222 for treatment advice. ATSDR says breathing moderate levels of boron irritates the nose, throat and eyes, and that ingesting large amounts can damage the stomach, intestines, liver, kidney and brain.
In Europe, boric acid carries a harmonised classification as a substance that may damage fertility, and the European Chemicals Agency added it to its Candidate List of Substances of Very High Concern on 18 June 2010 as toxic for reproduction. ATSDR says borates are used mostly to make glass, and also in fire retardants, cosmetics, soaps and cleaners, and some cockroach pesticides and wood preservatives.
Sources checked September 15, 2026. Every point below links the page it came from.
The sources behind this answer
- Medical referenceThe National Pesticide Information Center says boric acid is low in toxicity if eaten or on skin, but in the form of borax can be corrosive to the eye and irritating to the skin, and that eating it has caused nausea, vomiting, stomach aches and diarrhea. National Pesticide Information Center, Oregon State University ↗
- Medical referenceThe National Pesticide Information Center says products that contain boric acid have been registered for use in the United States since 1948, and reports that the EPA concluded boric acid is not likely to be carcinogenic to humans. National Pesticide Information Center, Oregon State University ↗
- Medical referenceThe National Pesticide Information Center advises following the first aid instructions on the product label after any boric acid exposure, and contacting the Poison Control Center at 800-222-1222 for additional treatment advice. National Pesticide Information Center, Oregon State University ↗
- Government sourceATSDR says breathing moderate levels of boron irritates the nose, throat and eyes, and that ingesting large amounts of boron can damage the stomach, intestines, liver, kidney and brain. ATSDR, CDC ↗
- Government sourceATSDR says borates are used mostly to produce glass, and also in fire retardants, cosmetics, soaps and cleaners, and some cockroach pesticides and wood preservatives. ATSDR, CDC ↗
- Regulatory filingECHA’s substance infocard says that under the harmonised classification approved by the European Union, boric acid may damage fertility. European Chemicals Agency, via web.archive.org ↗
- Regulatory filingOn 18 June 2010 the European Chemicals Agency added boric acid to its Candidate List of Substances of Very High Concern as toxic for reproduction. European Chemicals Agency, via web.archive.org ↗
Sources checked September 15, 2026. A brand statement is the company’s own claim, which we report but have not verified. Our grades are model-based estimates, not lab tests.