Chlorhexidine Mouthwash: What It Is, How to Use It and Side Effects

Chlorhexidine is an antiseptic that kills or slows the growth of many of the bacteria in plaque. It is not an antibiotic. It works in the mouth, is not absorbed into the body in any useful amount, and does not treat an infection that has spread. Mouthwashes containing it are widely sold, and some products need advice from a dentist or pharmacist.

It is not a replacement for brushing and cleaning between the teeth. It adds to them for a limited time. Plaque left on teeth turns into tartar, as explained in our guide on what plaque is.

Dentists most often suggest it for a short time when the gums are inflamed and cleaning is painful, in the days after gum treatment or a tooth extraction, or when a mouth ulcer or other condition makes brushing difficult. It is a short-term helper while the gums settle, usually alongside professional cleaning and better home care.

It is not a long-term daily mouthwash. The cause of bleeding or swollen gums is plaque and tartar, and those have to be removed. Read about gingivitis and swollen gums to understand the cause.

Use it exactly as directed on the label of the pack or as your dentist advises, including the amount to rinse with and the time to swish for. Spit it out and do not swallow it. Do not rinse with water straight afterwards, since that washes it away.

Toothpaste can reduce the effect of chlorhexidine, so leave a gap after brushing before you use it, and the usual advice is to wait at least half an hour. Your dentist may suggest using it at a different time from brushing, such as after lunch. Do not use it for longer than advised. Follow the label for how long it should be used.

The common side effects are brown staining of the teeth, tongue and fillings, an altered or reduced sense of taste, a dry or sore mouth and more tartar build-up. Staining is a surface effect, and a dentist can usually remove it with a professional clean once you stop. Taste usually returns after stopping. Some people feel a burning sensation, and a few have an allergic reaction. Stop the mouthwash and seek care if you have swelling of the lips or face, a rash or trouble breathing; swelling with difficulty swallowing or breathing needs a hospital emergency.

Ask a dentist, doctor or pharmacist first if the mouthwash is for a child, if you are pregnant or breastfeeding, or if you have ever had an allergy to chlorhexidine or other mouthwashes. Also ask if you have open sores in the mouth. Our gum treatment page describes the treatment that deals with the cause.