There is an old WebMD item about why your urine smells funny after eating asparagus. I only bring it up because the stalky delicacy is once again in season; delicious they are too from our local farm shop. Anyway, the WebMD item mentions that it’s the presence of a sulfur compound known as mercaptan in the asparagus (also found in rotten eggs, garlic, onions and skunk scent) that leads to the smell.
The article says, and I quote: “When your digestive tract breaks down this substance, by-products are released that cause the funny scent. The process is so quick that your urine can develop the distinctive smell within 15 to 30 minutes of eating asparagus.”
I’m not sure they’ve got that entirely straight though, it is definitely a sulfur compound being metabolised that releases the methanethiol giving urine the smell, and most researchers would suggest the amino acid methionine is the source. If it weren’t we’d also talk about asparagus poo as well as pee as the breakdown product would be present in both.