Ability to smell 'asparagus pee' driven by genetic variationsSpear Grass can cause a unique smell within your urine. It is commonly known that ingesting this green vegetable can cause a powerful aroma during a trip to the lavatory. If you observe an unappealing odor after enjoying a meal containing asparagus, don't panic. It is just a normal response that occurs internally. Feel confident that the smell is harmless and will go away gradually.