What Is Potassium Hydroxide?
FDA regulations at 21 CFR 184.1631 say potassium hydroxide is also known as caustic potash, potash lye and potassa, and describe it as a white, highly deliquescent caustic solid. The New Jersey Department of Health says it is used in making soap, as an electrolyte in alkaline batteries, in electroplating and lithography, and in paint and varnish removers, and that liquid drain cleaners contain 25 to 36% potassium hydroxide.
The New Jersey Department of Health calls potassium hydroxide a highly corrosive chemical and says contact can severely irritate and burn the skin and eyes, leading to eye damage. The NIOSH Pocket Guide lists symptoms including irritation of the eyes, skin and respiratory system, cough, sneezing, eye and skin burns, vomiting and diarrhea. The New Jersey Department of Health lists the NIOSH recommended exposure limit as 2 mg/m3, which should not be exceeded at any time.
As a food ingredient, 21 CFR 184.1631 affirms potassium hydroxide as generally recognized as safe (GRAS) as a direct human food ingredient used with no limitation other than current good manufacturing practice.
Sources checked September 15, 2026. Every point below links the page it came from.
The sources behind this answer
- Regulatory filingFDA regulations say potassium hydroxide is also known as caustic potash, potash lye and potassa, a white, highly deliquescent caustic solid. US FDA, 21 CFR 184.1631 (eCFR) ↗
- Regulatory filingFDA regulations affirm potassium hydroxide as generally recognized as safe as a direct food ingredient used under good manufacturing practice. US FDA, 21 CFR 184.1631 (eCFR) ↗
- Medical referenceThe New Jersey Department of Health says potassium hydroxide is used in soap, alkaline batteries and paint removers, and liquid drain cleaners contain 25 to 36 percent. New Jersey Department of Health ↗
- Government sourceThe New Jersey Department of Health calls potassium hydroxide highly corrosive and says contact can severely burn the skin and eyes. New Jersey Department of Health ↗
- Regulatory filingThe New Jersey Department of Health lists the NIOSH recommended limit for potassium hydroxide as 2 mg/m3, not to be exceeded at any time. New Jersey Department of Health ↗
- Government sourceThe NIOSH Pocket Guide lists potassium hydroxide symptoms including eye, skin and respiratory irritation, cough, burns, vomiting and diarrhea. NIOSH, CDC ↗
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.