The dosage of Rhizoma Coptidis is 2 to 5g, and the appropriate amount can be used externally. Huanglian belongs to the traditional Chinese medicine, for the buttercup plant Huanglian, triangular leaf Huanglian or Yunlian dry rhizome, with clearing heat and drying dampness (clearing heat, drying dampness), diarrhea and detoxification (eliminating the body of the fire toxicity and evil) effect. It is mostly used as a main treatment for damp-heat plumpness (stomach distension and discomfort), vomiting and acid swallowing (swallowing acid that rushes upward from the stomach to the oropharynx), damp-heat diarrhea (diarrhea caused by feeling damp-heat evils), high fever and dizziness, disturbed sleeplessness (disturbed heat in the heart and insomnia symptoms), blood-heat epistaxis (vomiting of blood and bleeding from the nose due to blood-heat), and the treatment of eczema, moist sores, and pus in the ear canals. The dosage of Rhizoma Coptidis for internal use is 2~5g, and for external use is moderate. Adverse effects of Rhizoma Coptidis include dizziness, tinnitus, nausea, shortness of breath and arthralgia due to overdose. Contraindications are not suitable for use with digitalis cardiac glycosides, and should not be used in combination with western alkaloids such as atropine, aminophylline and caffeine. Precautions have spleen and stomach deficiency cold (spleen and stomach weakness cold) people should not use, Yin deficiency and fluid injury people should be cautious. Chinese medicines or proprietary Chinese medicines need to be used under the guidance of a Chinese doctor to identify the evidence, and individuals should not use them blindly to avoid adverse consequences.