Asparagus is very popular in Europe as a vegetable. People in some countries prefer white variety which is not different but lacks chlorophyll as it is grown in areas of very low light.
Asparagus contains a non-toxic acid called Asparagusic acid. This acid contains sulphur element. When it is eaten, the acid in the stomach breaks down the Asparagusic acid into volatile sulphur compounds like mercaptan.
When a person who has consumed asparagus goes to urinate, the sulphur compounds evaporate very fast and get separated from urine and reach the nose giving rotten eggs or rotten cabbage like smell. Studies indicate that effect can be felt within 20 minutes after consumption of asparagus.