The ingredients in mouthwash that can be harmful in large amounts are:

• Chlorhexidine gluconate
• Ethanol (ethyl alcohol)
• Hydrogen peroxide
• Methyl salicylate

Many brands of mouthwash contain the ingredients listed above.

Symptoms of a mouthwash overdose include:

• Abdominal pain
• Burns and damage to the clear covering of the front of the eye (if it gets in the eye)
• Coma
• Diarrhea
• Dizziness
• Drowsiness
• Headache
• Low body temperature
• Low blood pressure
• Low blood sugar
• Nausea
• Rapid heart rate
• Rapid, shallow breathing
• Skin redness and pain
• Slowed breathing
• Slurred speech
• Throat pain
• Uncoordinated movement
• Unconsciousness
• Unresponsive reflexes
• Urination problems (too much or too little urine)
• Vomiting (may contain blood)

Seek medical help right away. Do not make the person throw up unless poison control or a health care provider tells you to.

Have this information ready:

• Person's age, weight, and condition
• Name of the product (ingredients and strength, if known)
• Time it was swallowed
• Amount swallowed

Your local poison control center can be reached directly by calling the national toll-free Poison Help hotline (1-800-222-1222) from anywhere in the United States. This national hotline will let you talk to experts in poisoning. They will give you further instructions.

This is a free and confidential service. All local poison control centers in the United States use this national number. You should call if you have any questions about poisoning or poison prevention. It does NOT need to be an emergency. You can call for any reason, 24 hours a day, 7 days a week.

Take the container to the hospital with you, if possible.

The provider will measure and monitor the person's vital signs, including temperature, pulse, breathing rate, and blood pressure.

Tests that may be done include:

• Chest x-ray
• Electrocardiogram (ECG)
• Endoscopy -- camera down the throat to look for burns in the esophagus and stomach

Treatment may include:

• Fluids through a vein (by IV)
• Medicines to treat symptoms
  
• Activated charcoal
• Laxative
• Breathing support, including a tube through the mouth into the lungs and connected to a breathing machine (ventilator)
• Kidney dialysis (kidney machine), in serious cases

The person may be admitted to the hospital.

How well someone does depends on the amount of mouthwash that was swallowed and how quickly treatment is received. The faster medical help is given, the better the chance for recovery.

Drinking large amounts of mouthwash may cause symptoms similar to drinking large amounts of alcohol (drunkenness). Swallowing large amounts of methyl salicylate and hydrogen peroxide may also cause serious stomach and intestine symptoms. It can also lead to changes in the body's acid-base balance.

Listerine overdose; Antiseptic mouth rinse overdose

Hoyte C. Caustics. In: Walls RM, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 143.

Nelson ME. Toxic alcohols. In: Walls RM, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 136.

Olives TD, Ling LJ. The alcohols: ethylene glycol, methanol, isopropyl alcohol, and alcohol-related complications. In: Bakes KM, Buchanan JA, Moreira ME, Byyny R, Pons PT, eds. Emergency Medicine Secrets. 7th ed. Philadelphia, PA: Elsevier; 2022:chap 71.

Updated by: Jesse Borke, MD, CPE, FAAEM, FACEP, Attending Physician at Kaiser Permanente, Orange County, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.