Nutrition Basics Why Eating Asparagus Makes Your Pee Stink By Shereen Lehman, MS Shereen Lehman, MS Shereen Lehman, MS, is a former writer for Verywell Fit and Reuters Health. She's a healthcare journalist who writes about healthy eating and offers evidence-based advice for regular people. Learn about our editorial process Updated on November 10, 2020 Medically reviewed Verywell Fit articles are reviewed by board-certified physicians and nutrition and exercise healthcare professionals. Medical Reviewers confirm the content is thorough and accurate, reflecting the latest evidence-based research. Content is reviewed before publication and upon substantial updates. Learn more. by Jonathan Valdez, RDN, CDCES, CPT Medically reviewed by Jonathan Valdez, RDN, CDCES, CPT Facebook Twitter Jonathan Valdez, RDN, CDCES, CPT is a New York City-based telehealth registered dietitian nutritionist and nutrition communications expert. Learn about our Medical Review Board Print Verywell / Alexandra Shytsman Some people notice their urine has a distinctive odor after eating asparagus. Often described as sulfurous or similar to cooked cabbage, the scent is due to the body's reaction to natural compounds found in the green stalks. If you've never eaten asparagus or are unfamiliar with the "asparagus pee" phenomenon, smelling that odor for the first time could be quite alarming. However, it is normal, though not all people experience it. In fact, a 2016 study found that roughly 60 percent of people of the (roughly) 2600 people studied didn't notice a strong characteristic odor in their urine after eating asparagus. According to research published in the journal Chemical Senses in 2011, the reason you may or may not recognize eau d'asparagus is two-fold. Some people are unable to smell it, while other people do not seem to have a reaction to asparagus. In both studies, researchers used DNA data to identify which genes, if any are responsible for the phenomenon, and came up with roughly 800 different possibilities. What Is Responsible for Smelly Asparagus Pee? For more than a century, scientists have sought to determine the precise chemical compound responsible for asparagus pee. Methanethiol was the first one to be blamed in 1891. Since then, many other compounds have been proposed as the possible stinkers—variations of sulfides, methanes, and butyl found in the vegetable. The latest culprit appears to be 1,2-dithiolane-4-carboxylic acid, better known as asparagusic acid. An otherwise harmless compound, asparagusic acid is found only in asparagus. It was identified as the major chemical precursor to the smell in a research review published in Perspectives in Biology and Medicine in 2013. Further studies show that in 4.7 hours, half of the asparagusic acid has been metabolized. Is the Smell a New Phenomenon? Asparagus has been around for thousands of years, but one of the first mentions of eau d' asparagus appeared in literature in the mid 1500s when botantist and physician Pietro Andrea Mattioli decribed multiple times the "stinking"odor that asparagus produced in urine. Benjamin Franklin also mentioned the asparagus-pee connection in his essay, "Fart Proudly," a paper urging scientists of the day to develop a method to change the offensive odor of expelled gas. He used asparagus as an example of how the various things that go into the body can affect the odors that come out of it. Many people describe asparagus pee as sulfur-like, so it's interesting to note that sulfur-containing fertilizers were first used to improve the flavor of asparagus late in the 17th century, and descriptions of asparagus pee began to appear shortly after that. Asparagus Cooking Methods There is no research to suggest that the manner in which asparagus is prepared has any impact on urine smell. Asparagus can be enjoyed raw, boiled, broiled, sautéed, or grilled. Unsure how to prepare asparagus? Try these recipes: Roasted or Grilled Asparagus Asian-Inspired Roasted Asparagus Asparagus-Mushroom Frittata Stir-Fried Asparagus With Cashews Asparagus and Ginger Chicken Stir-Fry 8 Delicious High Protein Vegetables 4 Sources Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Markt SC, Nuttall E, Turman C, et al. Sniffing out significant "pee values": genome-wide association study of asparagus anosmia. BMJ. 2016;355:i6071. doi:10.1136/bmj.i6071 Pelchat ML, Bykowski C, Duke FF, Reed DR. Excretion and perception of a characteristic odor in urine after asparagus ingestion: a psychophysical and genetic study. Chem Senses. 2011;36(1):9-17. doi:10.1093/chemse/bjq081 Mitchell SC. Asparagus, urinary odor, and 1,2-dithiolane-4-carboxylic acid. Perspect Biol Med. 2013;56(3):341-351. doi:10.1353/pbm.2013.0031 Ramamoorthy A, Sadler BM, van Hasselt JGC, et al. Crowdsourced asparagus urinary odor population kinetics. CPT Pharmacometrics Syst Pharmacol. 2018;7(1):34-41. doi: 10.1002/psp4.12264 By Shereen Lehman, MS Shereen Lehman, MS, is a former writer for Verywell Fit and Reuters Health. She's a healthcare journalist who writes about healthy eating and offers evidence-based advice for regular people. See Our Editorial Process Meet Our Review Board Share Feedback Was this page helpful? Thanks for your feedback! What is your feedback? Other Helpful Report an Error Submit