What Is Lye?
Lye is sodium hydroxide. ATSDR describes sodium hydroxide as very corrosive, generally used as a solid or a 50 percent solution, and says its other common names include caustic soda and lye. It says small amounts are sometimes used in drain and oven cleaners, and that using these products may expose you to it.
ATSDR says skin contact can cause severe burns with deep ulcerations, with pain and irritation within 3 minutes, though dilute solutions may not cause symptoms for several hours, and that contact with the eye may produce pain and irritation and, in severe cases, clouding of the eye and blindness. It says swallowing solid or liquid sodium hydroxide can cause spontaneous vomiting, chest and abdominal pain and difficulty swallowing, and that corrosive injury to the mouth, throat, esophagus and stomach is very rapid and may result in perforation, hemorrhage and narrowing of the digestive tract.
For skin contact, New Jersey's Department of Health says to quickly remove contaminated clothing, blot or brush off excess chemical, wash gently with large amounts of water for at least 30 minutes and seek medical attention immediately. The NIOSH Pocket Guide lists immediate eye irrigation, immediate water flushing of the skin, respiratory support if it is breathed in and immediate medical attention if it is swallowed.
Sources checked September 15, 2026. Every point below links the page it came from.
The sources behind this answer
- Government sourceATSDR describes sodium hydroxide as very corrosive, generally used as a solid or a 50 percent solution, and says its other common names include caustic soda and lye. ATSDR, CDC ↗
- Government sourceATSDR says small amounts of sodium hydroxide are sometimes used in drain and oven cleaners, and that using these products may expose you to it. ATSDR, CDC ↗
- Government sourceATSDR says sodium hydroxide on the skin can cause severe burns with deep ulcerations, with pain within 3 minutes, and that in the eye it may cause pain and, in severe cases, clouding of the eye and blindness. ATSDR, CDC ↗
- Government sourceATSDR says swallowing sodium hydroxide can cause vomiting, chest and abdominal pain and difficulty swallowing, and that corrosive injury to the mouth, throat, esophagus and stomach is very rapid. ATSDR, CDC ↗
- Government sourceFor skin contact with sodium hydroxide, New Jersey's Department of Health says to remove contaminated clothing, blot or brush off excess chemical, wash gently with large amounts of water for at least 30 minutes and seek medical attention immediately. New Jersey Department of Health ↗
- Government sourceThe NIOSH Pocket Guide lists first aid for sodium hydroxide as immediate eye irrigation, immediate water flushing of the skin, respiratory support if breathed in and immediate medical attention if swallowed. 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.