Why does my breath smell like that?

Specific breath odours can point to specific causes, from sulfur-producing tongue bacteria to ketones and, rarely, kidney or liver problems. These guides explain each smell and which ones need a doctor.

• Why does my breath smell like metal?A metallic smell on your breath most often comes from a little blood in your mouth, usually from gums that bleed when you brush or floss, or from a metallic...
• Why does my breath smell fruity or like acetone?Breath that smells fruity, like acetone or like nail polish remover means your body is making ketones and breathing some of them out. During fasting or a...
• Why does my breath smell like mothballs?No medical condition is known to make breath smell specifically like mothballs, and medical references do not use the term. When people describe their...
• Why does my breath smell like ammonia or pee?Breath that smells like ammonia or urine is a recognized sign of advanced kidney disease, when waste products such as urea and ammonia build up in the blood...
• Why does my breath smell like fish?Fishy breath most often comes from something you ate or from bacteria in the mouth, tonsils or sinuses, and it fades with time and cleaning. A fishy smell...
• Why does my breath smell like rotten eggs?Rotten-egg or sulfur breath is the classic smell of volatile sulfur compounds such as hydrogen sulfide, which are made by bacteria living in the coating on...
• Why does my breath smell like garlic?If you ate garlic, its sulfur compounds get into your blood and are breathed out for hours, so brushing only partly helps. If your breath smells like garlic...
• Why does my breath smell like alcohol when I haven't been drinking?If you have not been drinking, an alcohol-like smell on your breath is most often from something in your mouth, such as an alcohol-based mouthwash, or from...
• Why does my breath smell like vinegar?A vinegar-like, sour smell on the breath most often comes from acid reflux bringing stomach contents up, from something acidic or fermented you ate or...
• Why does my breath smell like sour milk or cheese?A sour-milk or cheesy smell on the breath usually comes from bacteria breaking down proteins in a tongue coating, in tonsil stones or in mucus dripping from...