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Why Do Your Sneezes Smell And What Does It Say About Your Health?

It’s nothing to sneeze at.


Dr. Beccy Corkill


Dr. Beccy Corkill

Custom Content Manager

Beccy is a custom content producer who holds a PhD in Biological Science, a Master’s in Parasites and Disease Vectors, and a Bachelor’s in Human Biology and Forensic Science.

Custom Content Manager

Man sneezing on a black background. Eyes closed mouth open.

Underlying health conditions can cause sneezes to smell sweet, sour, foul, or of ammonia. Image credit: Master1305/

Has someone ever sneezed beside you, and a few moments later you got hit with an unpleasant odor? Smelly sneezes can say a lot about a person and their health.

The occasionally smelly sneeze is normal – however, some prolonged smells may be a concern for which people should head to their medical practitioner.


There are four different categories of smelly sneezes: sweet, foul, sour, and ammonia.

Sweet smelling sneezes

Sweet-smelling sneezes could be a result of chemicals produced by bacteria in your sinuses, elevated ketones, or diabetic ketoacidosis.

Ketones are produced by the liver when there is not enough insulin in the body. This can happen when a person is on a keto diet. However, this could be a symptom of diabetic ketoacidosis and is a dangerous complication that is diabetes related.

Foul smelling sneezes

A horrid-smelling sneeze can be the result of a sinus infection.


According to the Centers for Disease Control and Prevention, a sinus infection (sinusitis) is when there is a fluid buildup in the sinuses (the air-filled pockets in the face). This build-up is a great environment for germs to grow, often viruses and some bacteria.

One of the symptoms of a sinus infection includes mucus dripping down the throat (also called a post-nasal drip) and bad breath. These two symptoms can contribute to the bad-smelling sneeze.  

Medical care should be sought out when the symptoms get worse after improving, symptoms last more than 10 days without improving, severe headaches or facial pain, or if there has been a fever for longer than 3-4 days.   

Sour smelling sneezes 

A sneeze that is sour smelling indicates bad breath. When you sneeze, saliva is expelled out of the nose – which means stinky saliva equals a sour-smelling sneeze.


If this smell is still occurring after a thorough brushing, flossing, and a swirl of mouthwash, then it may indicate gum disease.

Ammonia smelling sneezes 

One red flag for health is if a sneeze smells like ammonia, as this could indicate a serious issue related to the kidneys or liver.

For the kidneys, this can mean that the ammonia is not being excreted efficiently, which results in the build-up of exhaled ammonia.

The content of this article is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of qualified health providers with questions you may have regarding medical conditions.


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