WHAT DOES IT MEAN WHEN...
Chemical in asparagus creates that odd aroma

Dr. Scott Carstens
March 15, 2005

QUESTION: What does it mean when my urine smells
especially pungent after eating asparagus?

ANSWER: "Asparagus urine" is the result of a simple
chemical reaction. Asparagus contains a sulfur compound
called mercaptan. (It's also found in rotten eggs, onions
and garlic.)

When your digestive tract breaks down this substance, by-
products are released that cause the unusual scent. The
process is so quick that your urine can develop the
distinctive smell within 15 to 30 minutes of eating the
vegetable. However, not everyone has the experience. Only
some people appear to have the gene for the enzyme that
breaks down mercaptan into its more pungent parts.

Sometimes, it's the little non-life-threatening body
oddities that cause the most curiosity. Send us questions
about your niggling health mysteries and we'll try to find
out the answers.

Dr. Scott Carstens is an arthritis and internal medicine
specialist at Scripps Clinic.