In a normal person, there are usually two kidneys, one on each side of the crista, connected by their respective urinary ducts to the bladder, the organ that stores urine. However, some people are born with one kidney, called congenital isolated kidney; some people have one kidney removed due to other reasons (illness or trauma, etc.) and only one kidney is left; in addition, some people have two kidneys but one kidney is diseased and lost its function, so only one kidney works, called functional isolated kidney. Does it matter in these cases? In general, one intact kidney is sufficient to perform the daily work of urine production and detoxification and will not affect your daily work and life. However, you should be careful to protect the only kidney you have and try to keep it from getting sick; inform your doctor when you visit him/her due to illness, especially in terms of medication to avoid damage to the kidney as much as possible. In addition, we should pay attention to regular checkups to detect hidden kidney problems at an early stage and deal with them early.