Why Sneezes Smell and 4 Scents to Know

Sometimes you might notice a lingering odor after you sneeze and wonder why it’s happening or what it means.

Anthony G. Del Signore, MD, PharmD, director of rhinology and endoscopic skull base surgery at Mount Sinai Beth Israel in New York City, explains what various types of sneeze scents could say about your health.

Why Sneezes May Smell

“A sneeze is a sudden expulsion of air likely due to an irritant or irritation in the nasal cavity,” Dr. Del Signore says. Usually, these irritants are allergens like pollen or dust, environmental pollutants, or germs like viruses — in other words, substances your body wants to flush out.

While a random sneeze with a scent isn't a cause for concern, some aromas — like the four listed below — can indicate certain health issues if they occur frequently.

If you’ve been regularly noticing that your sneezes have a smell, you may want to contact a doctor, who can perform a health assessment and help you determine the cause and a treatment plan, if needed.

Your Sneeze Smells Sweet

If your sneeze smells sweet, like honey, it could point to elevated levels of ketones, Del Signore says. This can occur when you're on the keto diet, but it can also be a sign of something more serious, such as diabetic ketoacidosis, he says.

• Fruity-scented breath
• Shortness of breath
• Excessive thirst
• Frequent urination
• Nausea
• Vomiting
• Stomach pain
• Fatigue

A doctor can help determine whether you’re experiencing ketoacidosis, and they can give you suggestions for treatment and prevention.

It Smells Sour

A sour-smelling sneeze can definitely be a sign of tooth-related problems or gum disease, Del Signore says.

“Plaque has a distinct sour smell to it, so exposed roots and poor dentition carry the same scents,” he says. And when you sneeze, you expel that smell in your breath.

If your sneeze smells sour, you can schedule a checkup with your dentist, who can examine your mouth and suggest ways to improve your oral hygiene.

• Gastroesophageal reflux disease (acid reflux)
• Tonsil stones
• Liver or kidney disease
• Sjögren’s syndrome
• Certain head or neck cancers

If your dentist can’t pinpoint a reason for your bad breath or smelly sneezes, it’s best to reach out to a doctor, who can perform an assessment and help determine the cause.

Your Sneeze Smells Foul

If your sneeze has a putrid smell, it's probably due to a sinus infection, Del Signore says.

Those symptoms can all affect the scent of your sneeze.

But even though sinusitis is a common reason for foul-scented sneezes, it’s not the only one. Any infection in your mouth or nose can cause a foul odor, Del Signore says.

It Smells Like Ammonia

Sneezes that give off an ammonia aroma or a hint of urine should give you pause.

This is likely linked to kidney problems, Del Signore says. When you have a kidney issue, “ammonia is not excreted efficiently, and thus there is a buildup of exhaled ammonia,” he says.

Consider an ammonia-smelling sneeze to be a red flag, and contact your doctor as soon as possible so they can assess your health history symptoms to make a proper diagnosis.

How to Address Sneeze Odors

It’s perfectly normal for your sneeze to smell from time to time and isn’t a cause for concern. However, if you’d like to address an unpleasant sneeze scent, the first step is to determine the root cause, then take steps to reduce or eliminate it.

For recurring sneezes with a smell, a doctor can evaluate your health history and perform an examination to determine whether an underlying health condition is responsible for the scent.

The Takeaway

• While an occasional sneeze with a scent isn’t a cause for concern, a persistent or distinctive odor may point to an underlying health condition or dental issue.
• Four sneeze aromas to take note of include a sweet smell, a sour smell, a foul smell, or an ammonia-like smell.
• A doctor can help diagnose the reasons for a recurring sneeze scent and may suggest a treatment plan or tips for reducing the smell.