The leaves of the tree, which contain lots of vitamin C, are used to make medicine. Birch is used for infections of the urinary tract that affect the kidney, bladder, ureters, and urethra.It is also used as a diuretic to increase urine output.ore evidence is needed to rate the effectiveness of birch for these uses. 1  Skin growths from sun damage (actinic keratosis). 2  Arthritis. 3  Hair loss. 4  Rashes. 5  Conditions of the urinary tract. 6  Achy joints (rheumatism). 7  Other conditions.