Take hair from the area near the female genitalia, cut it into pieces, and burn it to ash. Mix with water and administer one *cun* cube (a traditional Chinese volume measure) per dose. Administer three times daily. When urination becomes smooth and slight swelling occurs at the glans penis/vulva, the patient will recover.
If the patient is male, take male hair and burn it to ash for use.
The Classics state: Regarding the disease of "Yin-Yang Exchange" (mutual transmission of pathogenic factors after sexual intercourse following a febrile disease), the patient experiences heavy body sensation, shortness of breath, urgency and tension in the lower abdomen, or spasms drawing into the genital region, heat rushing up to the chest, heaviness of the head making it difficult to lift, visual disturbances (seeing spots), and stiffness/spasms of the knees and calves. This formula is indicated for such cases. According to analysis, when a major illness has just resolved but residual pathogens remain, engaging in sexual intercourse causes the Qi of both parties to interact, leading to mutual transmission of the disease. Investigating the root of the pathology, the pathogen enters via the anterior yin (genitals); therefore, it is necessary to guide the pathogen out through the same route. Thus, recovery is only achieved once urination is unobstructed. The formula uses only calcined hair as a single ingredient, relying on the principle that substances with similar affinities attract each other ("like responds to like"). These are ancient secret formulas whose efficacy is often beyond ordinary comprehension; they generally follow this pattern.