Hydrangea was used widely by the Cherokee Indians and, later, European settlers to treat stones in the urinary tract. It is known to help remove uric acid accumulations from the body, cleanse the kidneys, and soften deposits. It aids in the passage of stones and helps prevent their reoccurrence. It also deters infection, soothes inflammation, and strengthens the capillaries. Hydrangea is used in the treatment of arteriosclerosis, arthritis, bladder stones, backache due to kidney problems, capillary fragility, cystitis, dropsy, dysuria, gout, kidney stones, nephritis, prostatitis, urethritis, and urinary tract infection. Topically, hydrangea can be used as a compress or poultice to treat burns, sprains, tumors, and wounds.
Excessive amounts can cause gastrointestinal distress, dizziness, and chest congestion. Hydrangea is not recommended for long-term use or during pregnancy. Use just the root or rhizome; there have been some reports of the flowers and leaves causing toxicity in humans.