Under the premise of reasonable use of medication, cinnamon sticks are generally not harmful to the kidneys.
Gui Zhi is pungent, sweet and warm in nature; it belongs to the heart, lung and bladder meridians. It has the efficacy of warming the meridians and channels, sweating and relieving the muscles (relieving the evil qi on the surface of the skin), assisting yang in transforming qi, and leveling the flushing and descending the rebellious qi (using qi descending medicines to solve the upward rebellious qi).
Gui Zhi can be used for the treatment of wind-cold surface evidence, cold condensation pain, palpitations, phlegm (water metabolism disorders formed by the pathological products), edema and other conditions, the product of pungent and warm to help heat, easy to injure the yin and move the blood, where the external heat disease, yin deficiency and fire, blood heat paranoia (heat caused by the blood abnormalities out of the evidence, etc.), are to be avoided. Pregnant women and people with excessive menstruation should be cautious.
Gui Zhi in the reasonable use of the scope of the cinnamon stick has not been found to have reports of kidney damage, but the specific medication should be taken under the guidance of a doctor, do not blindly self-medication, so as not to delay the condition.