Side effects of drinking Listerine vary depending on the dose taken; ingesting more than the amount used for rinsing the mouth produces symptoms ranging from nausea, upset stomach and headache to slowed breathing, slurred speech and unconsciousness. Listerine, like many mouthwashes, contains alcohol as one of its primary ingredients. Since the consequences of ingesting Listerine may be significant, people who have consumed too much should call (or have someone else call if they are unable) a local emergency or poison control center, say experts at the University of Maryland Medical Center (UMMC).
Drinking large quantities of Listerine is referred to as a Listerine overdose or a mouthwash overdose. It may happen intentionally or accidentally, and poses the same risks for people of all ages.
Like drinking too much alcohol, having too much Listerine in the body produces toxic effects ranging from abdominal discomfort and pain to severe problems such as coma and loss of movement. Excess Listerine consumption may also affect the eyes by burning or damaging corneas. People suffering from Listerine overdose may feel tired, dizzy and have throat pain. Other symptoms include reduced blood pressure, blood sugar and body temperature, say experts at the UMMC.
When victims of Listerine overdose arrive at the hospital, doctors use several treatments for countering the poison. They might administer a laxative, perform kidney dialysis, administer a breathing tube or pump the patient's stomach using a gastric lavage. Prognosis depends on amount of mouthwash swallowed and when patients receive medical treatment.