Many possible causes. Of smelly urine: concentrated due to dehydration & low fluid intake causes a strong smell. Urinary infections may be most common cause of foul smelling urine and often alert subjects to presence of uti. Some antibiotics such as Amoxicillin &cipro cause smelly urine as does consuming large volumes of coffee, ie >6cups/day. Classically asparagus has distinctive smell. Others r liver disease & diabetes.