If you’re having a conversation with friends or colleagues and find that they’re doing a hard lean away from you, it may signal something more than a little embarrassing. Your breath reeks. Everyone knows that certain foods like garlic and onions can cause a stink bomb in your mouth, but there are also certain drinks that are especially bad when it comes to your breath.

Bad breath usually stems from one of three things, explains Gigi Meinecke, DMD, a dentist with the Academy of General Dentistry based in Potomac, Maryland: acid reflux from the stomach; post-nasal drip from air passages; and substances called volatile sulfur compounds, or VSCs, in the mouth. The mouth is home to tons of species of bacteria that survive on the food you eat, and when bacteria digest your meals, they produce stinky VSCs, which are in turn responsible for malodorous breath.

Part of taming bad breath is staying hydrated–but not all liquids are created equal. Some drinks will actually feed the bacteria that produce VSCs and intensify stinky breath. Find out which drinks are the worst for your breath, plus one that can actually make breath smell better.

Coffee

Millions of people may love it, but most of us aren’t so crazy about one unfortunate side effect: coffee breath. Coffee itself is high in smelly sulfur, which contributes to stinky breath.

If you thought swapping in tea was the answer, Health‘s contributing nutrition editor Cynthia Sass, MPH, RD, says to think again: “Too much caffeine can dry out your mouth, which increases odor, because saliva helps wash away bacteria and food particles that cause bad breath.”

Alcohol

In an April 2018 study published in the journal Microbiome, researchers examined the bacterial community of spit samples from more than 1,000 healthy volunteers between the ages of 55 and 84. They found a higher concentration of “bad” bacteria linked to gum disease–a bad breath trigger–in volunteers who reported drinking alcohol.

On top of altering the bacteria in your mouth, “alcohol can also trigger acid reflux, which causes stomach acid to creep up into the throat, and that acid has an odor,” Sass adds.

Carbonated beverages

There’s acid in soda and other bubbly drinks that gives them their fizz–but acid is a major player in bad breath. Acidity dries out your mouth, allowing bacteria and food to linger, ultimately causing bad breath, Dr. Meinecke says.

What to drink to fight bad breath

Good old H2O is your best option. Sass suggests getting into the habit of drinking a glass after meals. “This can help wash away food particles that can contribute to bad breath,” she says.

Saliva is 99% water, Dr. Meinecke explains, so staying hydrated ensures you create plenty of the stuff, which is needed to keep your mouth clean and fresh. Water is also odorless and doesn’t provide anything for bacteria to feed on, meaning they can’t produce smelly VSCs. “As you drink water, it cleans off your tongue where those bacteria and their VSCs are trapped,” she says.

If water is too boring for you, spice it up by adding some mint leaves for a burst of freshness. For an even tastier option, Dr. Meinecke recommends making an infusion. “Cut up a slice of watermelon, and put it in a jar with some basil leaves. Fill the jar with water, and let it sit in the fridge for a few hours.”