Mouthwash is a liquid you swish around in your mouth and then spit out to clean your teeth, freshen your breath, and kill bacteria. Most mouthwashes contain ingredients like mint flavoring (which creates that fresh, tingly feeling) and substances that fight germs.

You use mouthwash by pouring a small amount into your mouth, swishing it around for 30 seconds or so, then spitting it into the sink. It reaches places your toothbrush might miss, like between teeth and along your gums. Some mouthwashes contain fluoride, which strengthens tooth enamel the same way fluoride in toothpaste does.

While mouthwash helps with oral hygiene, dentists emphasize that it works best as a supplement to brushing and flossing, not a replacement. The word can also be used as a verb: you might use mouthwash after eating something with a strong smell like garlic. Some types of mouthwash are antiseptic, meaning they kill bacteria that cause bad breath and gum disease. Others focus mainly on freshening breath or whitening teeth.