There are no studies related to the maximum harmful effects of Xianhe Cao. Side effects may include palpitations and flushing after taking it, while others are not yet clear. Xianhecao has a bitter, astringent flavor and is flat in nature, entering the liver meridian and heart meridian. It can be used both internally and externally to stop diarrhea, stop bleeding by astringency (using drugs with astringent effect to treat bleeding conditions), stop malaria, detoxification, and is used in the treatment of carbuncle, swelling, sores and poisons, hemorrhagic leakage, hemoptysis, malaria, vomiting of blood, labor injuries, bloody diarrhea, and itchy vagina and hypoglossia, among others. Xianhecao can cause palpitations, facial congestion and flushing and other adverse reactions, contraindications are not yet clear. If necessary, please use it under the guidance of a professional Chinese medicine practitioner, and do not use Xianhecao blindly on your own.