Food history Musings Recipe Vegetables

Food For Thought: What’s that smell?? (…and an asparagus recipe)

Asparagus makes pee smell bad. That should come as no surprise to – well – just about everyone. In fact, about 50% of people report some sort of pungent odor as soon as 15 minutes after eating the vegetable. I assume that the other 50% aren’t weirdos who need to inform others about the smell of their bodily functions, or who wonder why those smells happen in the first place.

Well, this weirdo started pondering that very idea after making some simple roasted asparagus (listed below the forthcoming information), and thus; this post.


Apparently, the stench of asparagus-urine is a well-recorded fact, which has been observed (and recorded) for centuries. The vegetable itself appears in Greek myth, may have been known to the ancient Egyptians, and is discussed in the records of ancient Rome. The effects on the smell of urine, however, aren’t specifically recorded (again, probably because they had better things to do) until 1735, when the following line appears in an essay by Dr. John Arbuthnot, of the London College of Physicians: “Of the Stems of Plants, ſome contain a ſine Aperient Salt, and are Diaretick and Saponaceous, as Aſparagus which affects the Urine with a Fetid Smell (eſpecially if cut when they are White) and therefore have been ſuſpected by ſome Phyſicians as not friendly to the Kidneys, when they are older and begin to ramify they loſe this quality.”

It’s theorized that since Arbuthnot’s statement coincides with the agrarian revolution, the distinct asparagus-pee smell was never noticed (or didn’t happen) until the use of sulfurous compounds in fertilizers became commonplace.

Which brings us to the science portion of our evening.

Scientists – which, let’s face it, should (like myself) probably be investing their time in more important ways – have determined that the cause of the smell is a chemical called “asparagustic acid”. This poorly researched chemical, which as the name indicates only appears in the eponymous veggie, is thought to be a sulfur compound that breaks down during digestion, and is then off-gassed during urination. That’s about as specific as I can be, because – from what I was able to find in my cursory research – while there have been various investigations of the subject, no studies have been able to definitively show how the human body metabolizes asparagus.

However, studies HAVE shown that while most people both produce and can smell asparagus pee, there are some who either don’t get it, can’t smell it, or both.

So while science keeps chuggin’ along in a effort to answer the truly important questions, like “what is the meaning of life?” and “why does my pee smell?”, I’ll leave you with a final thought (and then a recipe):

Benjamin Franklin once wrote a satirical article to the Royal Academy of Brussels, in which he anecdotally referred to the odor-producing powers of asparagus. In the article, he facetiously undermined what he deemed to be their fruitless and foolhardy “scientific pursuits”, by proposing they find a solution to “fetid wind” though some ingested means. In other words, one of the American founding fathers essentially argued that if asparagus can make pee smell, this conglomeration of self-aggrandizing scientists should be able to, quickly and easily, produce a “pill”, “powder”, or “limewater” capable of neutralizing stinky farts.

So, if you’ve learned nothing else, at least now you know that even Benjamin Franklin thought that farts were funny. 🙂

Roasted Asparagus:



  • 1 bunch of asparagus – cleaned
  • Extra virgin olive oil
  • Salt and pepper (and other spices, if you want)
  • 1/4 cup fresh grated Parmesan cheese

Preheat the oven to 400 degrees.

Place the asparagus on a cookie sheet, and toss them in a tablespoon (or two) of the olive oil – enough to coat all of the stems.

Sprinkle with salt and pepper (and other spices if you choose; something like an Italian spice mix works well in this case) and toss to coat. If you need more exact measurements, go with a 1/2 teaspoon of each, and adjust as necessary (you can always season after the fact as well).

Spread them out on the sheet so they aren’t overlapping (much).

Sprinkle the seasoned asparagus with all of the cheese.

Roast for at least 6 minutes, but maybe as much as 12 or 15, for thicker stems.

Serve and enjoy, hopefully with something else equally delicious!



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