Why does my breath smell like garlic?

Garlic smell has two parts. Some comes from food residue in the mouth, which brushing removes. The rest comes from sulfur compounds that are absorbed, carried in the blood and exhaled from the lungs. The MSD Manual notes others can smell garlic on your breath 2 or 3 hours after you eat it, long after the food has left your mouth. That is why mints and mouthwash only mask it until your body clears the compounds.

Garlic supplements and concentrated garlic oil capsules contain the same compounds and can cause the same odor, sometimes more strongly.

• Too much selenium. Cleveland Clinic lists garlic odor to the breath or sweat, a metallic taste, hair loss, brittle or discolored nails, diarrhea, nausea and fatigue as signs of selenium toxicity from supplements. Check every product you take, because selenium appears in many multivitamins and "immune" blends.
• DMSO (dimethyl sulfoxide). Used as a prescription bladder treatment and also sold unregulated as a topical liquid or gel. A systematic review explains that part of it is converted to dimethyl sulfide, which gives a garlic- or oyster-like smell when exhaled. Garlic-like breath was one of its most commonly reported side effects.
• Organophosphate pesticides. Some insecticides give off a garlic-like odor, and clinicians use that smell as one clue to poisoning. A 2025 case report describes a man first thought to be drunk whose garlic odor helped identify the real problem. This is rare and comes with other symptoms, but it is an emergency.
• Liver failure. Cleveland Clinic explains that one of the main compounds in fetor hepaticus, dimethyl sulfide, smells garlicky, and the overall odor is described as musty, sweet and sometimes like rotten eggs and garlic.

Write down every supplement, medicine, cream and chemical you have used in the last week, including garden or pest products, then compare it with the table above. Do not stop a prescribed medicine without speaking to the prescriber. If a child may have swallowed supplements or a household chemical, call Poison Help (1-800-222-1222 in the US) even if they seem fine. If you notice a garlic smell along with any signs of poisoning, call emergency services rather than driving yourself.

Brushing your teeth, cleaning your tongue and rinsing removes the part of the smell that sits in your mouth, so it is still worth doing after a garlicky meal. Water and time handle the rest. There is no evidence that any product speeds up how fast your body clears garlic compounds from the lungs. For food-related breath in general, see our guide to bad breath causes.