Tacrolimus lowers your body's immune system. The immune system helps your body fight
infections. The immune system can also fight or "reject" a transplanted organ such as a liver or kidney.
This is because the immune system treats the new organ as an invader.
Tacrolimus is used together with other medicines to prevent your body from rejecting a heart,
liver, or kidney transplant.
Tacrolimus may also be used for other purposes not listed in this medication guide.