Chuan Huanglian refers to the yellow dock produced in Sichuan, which has the efficacy of drying dampness and clearing heat, diarrhea and detoxification (removing fire and toxicity in the body), and is able to treat damp-heat diarrhea (diarrhea caused by dampness-heat), vomiting and other illnesses. Chuan Huanglian is bitter and cold in nature, with the effects of drying dampness and clearing heat, diarrhea and detoxification. It can be used for treating damp-heat in the spleen and stomach in the middle jiao (spleen and stomach feeling damp-heat evil), damp-heat diarrhea, vomiting and abdominal pain, dysentery with pus and blood (diarrhea with pus and blood in feces), etc. It can also be used for treating heart-heat hyperactivity. It can also be used in the treatment of hyperactivity of heart fire, high fever and dizziness, palpitation (rapid heartbeat, often accompanied by panic), restlessness, blood-heat paranoia (heat evils causing blood to go out abnormally), epistaxis, vomiting of blood, stomach fire and toothache, and so on. Adverse effects of taking Chuan Huanglian are not clear. It is bitter, cold and dry, and is prone to depletion of yin and fluid, so it should be used with caution in cases of yin deficiency and fluid injury. At the same time, a large amount of prolonged use is likely to damage the spleen and stomach, so it is contraindicated for those who are weak in spleen and stomach (spleen and stomach weak and cold). If you feel unwell, it is recommended to go to the hospital in time, and under the guidance of a professional physician, make a reasonable choice according to your own situation.