It is said that in a venerable British men's club there is a sign reading "DURING THE ASPARAGUS SEASON MEMBERS ARE REQUESTED NOT TO RELIEVE THEMSELVES IN THE HATSTAND."

t was originally thought this was because some of the population digested asparagus differently than others, so that some people excreted odorous urine after eating asparagus, and others did not. However, in the 1980s three studies from France,[28] China and Israel published results showing that producing odorous urine from asparagus was a universal human characteristic. The Israeli study found that from their 307 subjects all of those who could smell 'asparagus urine' could detect it in the urine of anyone who had eaten asparagus, even if the person who produced it could not detect it himself.[29] Thus, it is now believed that most people produce the odorous compounds after eating asparagus, but only about 22% of the population have the autosomal genes required to smell them.[