There are no studies related to the harmful effects of Gui Zhi. Gui Zhi has the efficacy of assisting yang to transform qi, sweating and relieving muscle (removing evil qi from the surface of the skin), warming the meridians, and calming the flushing and subduing qi, and is often used for wind-cold and cold. Gui Zhi is an antidote to cold (removing cold from the surface of the skin) in the family of antidote to cold (removing cold from the surface of the skin), the family is the dried shoots of Cinnamomum cinnamomi in the family of Camphoraceae. Cinnamon sticks are pungent, sweet and warm in nature, and are used in the bladder, heart and lung meridians, both internally and externally. Cinnamon is used in the treatment of palpitation (accelerated heartbeat, often accompanied by panic), wind-cold flu, phlegm (pathological products formed by impaired metabolism of water and fluid), epigastric and abdominal cold pain (cold and painful sensation in the stomach and abdomen), oedema, paralytic pain in the joints, menstrual closure of blood and cold and running dolphin, etc. It is also used in the treatment of fever and high heat, and in the treatment of yin deficiency and fire. Gui Zhi should be used with caution in febrile illnesses with high fever, yin deficiency and fire exuberance (deficiency of yin and essence in the body, resulting in hyperactivity of deficiency fire), and blood-heat paranoia (heat causing blood to go out abnormally). Adverse effects of Gui Zhi are not known. If needed, please use under the guidance of a professional Chinese medicine practitioner to avoid delay.