Xiangru Yin (Elsholtzia Drink): Clearing Heat and Dispelling Summerheat

During the hot summer season, people are most susceptible to summerheat evil and various externally contracted diseases. Patients may present with feverish body and flushed face, vexation and thirst with a desire to drink, fatigue and profuse sweating, scanty dark urine, and even debility and lack of qi, skin allergies, eczema, sores and ulcers, a red tongue with a rapid or flooding and large pulse. In such cases, a formula that clears heat and dispels summerheat is needed; Xiangru Yin is the representative formula for clearing heat and dispelling summerheat.

The source of Xiangru Yin is Xiangru San (Elsholtzia Powder) from Taiping Huimin Hejiju Fang (Formulary of the People’s Benefaction Bureau of the Taiping Era). The original formula reads: "One jin of Xiangru (Elsholtzia, earth removed), half a jin each of white hyacinth bean (stir-fried slightly) and Houpo (Magnolia bark, coarse bark removed, prepared with ginger juice until cooked). The above are ground into coarse powder; for each dose take three qian, add one cup of water and one fen of wine, decoct to seven-tenths, remove the dregs, cool in water. Take two doses in succession, regardless of the time." The main action of Xiangru San is to dispel summerheat and release the exterior, and to transform dampness and harmonize the middle. The decocted liquid of Xiangru San must be taken cold, because when Xiangru is taken orally, taking it hot rather than cold easily causes vomiting. In addition, like Mahuang Tang, this kind of sweat-promoting medicine easily damages the healthy qi, so weak patients should not take it.

Later, Wu Tang (Wu Jutong) of the Qing dynasty further developed Xiangru San in Wenbing Tiaobian (Systematized Identification of Warm Diseases). On the basis of Xiangru San, he added two acrid-cool exterior-releasing herbs, Jinyinhua (Honeysuckle flower) and Lianqiao (Forsythia fruit), to form Xinjia Xiangru Yin (Newly Augmented Elsholtzia Drink), used to treat summer externally contracted syndromes. The formula is: "Two qian of Xiangru, three qian of Jinyinhua, three qian of fresh hyacinth bean flower, two qian of Houpo, two qian of Lianqiao." The decocting method is: "Boil five cups of water down to two cups; take one cup first; once sweating occurs, stop further doses; if no sweating, take again; when the whole dose is finished and still no sweating, prepare another."

Both formulas are named after Xiangru, which acts as the monarch herb and plays the principal role. According to traditional TCM theory, Xiangru is acrid in flavor and slightly warm in nature, enters the Lung and Stomach meridians, and promotes sweating to relieve summerheat, transforms dampness and promotes urination. It mainly treats summer contraction of wind-cold with internal damage by dampness, aversion to cold and fever, headache without sweating, epigastric and abdominal pain, vomiting and diarrhea, difficult urination, edema, and similar conditions.

Xiangru not only clears heat and dispels summerheat, reduces fever and releases the exterior, but also promotes diuresis and relieves edema. When used to release the exterior and dispel summerheat, the dosage should be small and it should not be decocted for long; when used to promote diuresis and relieve edema, the dosage should be large and it should be decocted for a long time. Therefore, when using Xiangru Yin, attention should be paid to whether the patient’s fever is more prominent, or whether scanty or blocked urination is more prominent; the dosage and decocting method of Xiangru should be determined by the patient’s chief complaint.

The diuretic and edema-relieving function of Xiangru can also be used for other diseases, such as nephritic edema, or ascites caused by cirrhosis and various cancers. When using Xiangru to promote diuresis and relieve edema, it is best to combine it with Baizhu (Atractylodes macrocephala). Seng Shen Ji Fang records a formula called "Xiangru Zhu Wan" (Elsholtzia-Atractylode Pill), composed of "one jin (sixteen liang) of Xiangru and seven liang of Baizhu": Baizhu is ground into powder, Xiangru is strongly decocted, and the Xiangru liquid is mixed with the Baizhu powder to form pills the size of a parasol tree seed, taken orally to treat "sudden water-wind edema, edema, or water within sores, with the whole body swollen"; this condition resembles edema caused by nephritis.

Modern pharmacological studies have confirmed that Xiangru has an antipyretic effect, and the antipyretic effect is more pronounced after three consecutive doses. In TCM treatment of fever, no matter which formula is used, the medicine is not taken in the routine manner of twice or three times a day, morning and evening (or morning, noon and evening). Instead, as advocated in Shanghan Lun, one "observes over a full cycle of twenty-four hours": if the patient has not returned to normal temperature after taking the medicine, dosing continues without interruption. Some doctors consider dosing every two hours appropriate; however, when treating fever in myself and my family, I usually give a dose every half hour to one hour. Once the fever has abated, the body is cool and free of sweat, and the person feels refreshed, I then have a bowl of two-gruel (rice and millet cooked together) and take a hot bath, and recovery is complete; generally only about half a day of treatment is needed.

Xiangru has a marked inhibitory effect on the spasmodic motility of the gastrointestinal tract, and a marked promoting effect on gastrointestinal propulsion, with smaller doses of Xiangru producing a more pronounced effect than larger doses. The reason Xiangru is commonly used for summer colds is mainly that summer colds are mostly accompanied by gastrointestinal symptoms, such as nausea and vomiting, or diarrhea and abdominal pain, all of which Xiangru can address. In TCM treatment of colds with feverish body and absence of sweating, Mahuang Tang is commonly used in winter and Xiangru Yin in summer, for the same reason.

Modern pharmacological studies also show that Xiangru has antibacterial and antiviral effects. The volatile oil or water decoction of Xiangru has a strong inhibitory effect on Escherichia coli, beta-hemolytic streptococcus, Salmonella typhi, Staphylococcus aureus, Neisseria catarrhalis, Shigella flexneri, and others. It has a significant inhibitory effect on influenza A virus and ECHO virus (ECHO11), and can efficiently inhibit hepatitis B virus surface antigen.

In addition, folk medicine also commonly uses Xiangru to treat various skin diseases and mouth ulcers. Taken internally or applied externally, Xiangru can treat ordinary eczema and scrotal eczema; gargling with Xiangru decoction is more effective than boric acid solution for oral ulcers. Xiangru can also treat halitosis; Qianjin Fang records a formula for halitosis: take a handful of Xiangru, decoct in water and hold in the mouth. Halitosis is generally caused by Helicobacter pylori; the fact that Xiangru treats halitosis may be due to its inhibitory effect on H. pylori.

White hyacinth bean or hyacinth bean flower is a spleen-strengthening herb, and Houpo is a dampness-transforming herb. Summer externally contracted syndromes are often accompanied by gastrointestinal symptoms such as indigestion, diarrhea, dysentery and vomiting; in this formula, white hyacinth bean and Houpo assist Xiangru in resolving some of the accompanying symptoms of summer-damp cold. Jinyinhua and Lianqiao belong to heat-clearing and exterior-releasing herbs; adding these two to Xinjia Xiangru Yin also assists Xiangru and strengthens the exterior-releasing and fever-reducing effect of the formula.