There is no therapeutic effect of taking fishweed boiled in water for dry cough without phlegm.
Fishweed is the fresh whole grass or dry ground part of Houttuynia cordata, family Sambucus. It is pungent in flavor, slightly cold in nature, and belongs to the lung meridian, with the effect of clearing away heat and removing toxins, eliminating canker sores and draining pus, and diuretic and diaphoretic (to improve the problem of dribbling in urine, and the problem of small amount of urine not being able to get through).
Fishwort is used for lung carbuncle and pus, phlegm-heat asthma and cough, hot diarrhea, heat drenching (burning and stinging pain is obvious when urinating, accompanied by frequent urination and urgency, and discomfort of traction in the abdomen), carbuncle and sores. Adverse effects of the drug are not known. It is contraindicated in deficiency-cold syndrome and yin sores and ulcers.
Dry cough without phlegm generally belongs to yin deficiency and dry cough, and can be identified using almonds, winter flowers, maitake, honey and other moistening of the lungs and relieving cough traditional Chinese medicine. Fishweed is generally used for phlegm-heat cough.
If there is a need for medication, it is recommended that it be used under the guidance of a professional physician, and not blindly self-medication.