There is no research related to the hazards of boiling dog’s tail grass in water, it is recommended to follow the doctor’s prescription for medication. The dog’s tail grass belongs to the clearing of heat and detoxification (clearing the body of heat and toxicity) medicine, clinically used in the treatment of wind-heat colds, jaundice and so on. Dogwood has a sweet, light flavor and is cool in nature. It has the efficacy of clearing the liver and brightening the eyes (clearing the liver fire to promote the recovery of eyesight), relieving heat and dampness, and is used in the treatment of eye redness and swelling, jaundice, and pediatric chancre (a kind of children’s chronic disease manifested by emaciation, dietary anomalies, abdominal distension, and thinning of hair withered and yellowed, etc.). It can also be used to treat carbuncle boils (a skin disease that refers to severe furuncles), mumps, common warts, and so on. Dog’s-tail grass is cold in nature, people with cold spleen and stomach (spleen and stomach weak and cold) should be cautious of using dog’s-tail grass to boil water to drink. Adverse effects of Dog’s Tail Herb are not known. People who are allergic to dog’s tail grass are not allowed to drink water boiled with dog’s tail grass. If necessary, please use under the guidance of a professional Chinese medicine practitioner.