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Mahuang (Ephedrae Herba): Taste slightly bitter, nature warm. It is the principal herb for inducing sweating. It penetrates and reaches all organs and meridians of the whole body, with its main therapeutic scope being the expulsion of Wind-Cold from the Taiyang (Greater Yang) channel. Therefore, *Shennong Bencao Jing* (Divine Farmer's Materia Medica) states that it treats headache and other syndromes caused by Wind-stroke and Cold damage, and also states that it treats cough and rebellious Qi, because it is good at searching out Lung Wind and can drain the Lung to calm wheezing. The statement that it breaks up masses and accumulations is because it can penetrate outside the skin pores and also deeply into accumulated phlegm and coagulated blood, allowing drugs that dissolve hardness and transform stasis to achieve efficacy alongside it. Moreover, its nature is good at promoting urination; it not only travels through the Taiyang channel but also enters the Taiyang fu-organ (Bladder), and can further extend from Taiyang to Shaoyin (Lesser Yin) (thus it is used in Shaoyin Cold Damage syndromes), and can treat white and hard carbuncles and ulcers, as well as Yin toxicity that knots and does not dissipate.

Taiyang serves as the outer covering of the body, which is the skin and hair, a function also governed by the Lung. When Wind-Cold invades the person, it not only enters the Taiyang channel but must also involve the Hand-Taiyin Lung channel, often resulting in symptoms of cough and slight wheezing. Mahuang involves the Hand-Taiyin channel and is an essential drug for expelling Cold and searching out Wind. Therefore, while herbs that induce sweating are not limited to Mahuang, *Shanghan Lun* (Treatise on Cold Damage) uses Mahuang Tang exclusively for Taiyang Cold Damage with no sweating, because it treats the Foot channels while taking care of the Hand channels.

Herbs that promote urination, those with hollow stems, often also induce sweating, such as Mutong (Akebiae Caulis) and Pianxi (Polygoni Avicularis Herba). Herbs that induce sweating, those with hollow stems, often also promote urination, such as Mahuang and Chaihu (Bupleuri Radix). In Taiyang channel diseases of Cold Damage, the pathogen often invades the Taiyang fu-organ (Bladder), causing lingering for many days without resolution. Mahuang treats the pathogen in the channel, and can also treat the pathogen in the fu-organ. This is because the pathogen in the channel is resolved through sweating, while the pathogen in the fu-organ can be resolved through urination. Those in later generations who use other drugs to replace Mahuang have likely not carefully examined this principle.

For syndromes of Wind-Water edema, *Jingui Yaolue* (Essential Prescriptions of the Golden Cabinet) treats them with Yuespi Tang (Dispersing the Spider Decoction), where Mahuang is the chief herb, utilizing its ability to dispel Wind and promote urination. In my usual clinical practice using this prescription, if the patient sweats after taking the medicine, urination immediately becomes smooth, and the swelling subsides. However, in this formula, Mahuang is used together with Shigao (Gypsum Fibrosum); the power of Gypsum is originally sufficient to restrain Mahuang, so there are cases where sweating does not occur after ingestion. Now, modifying this formula: before taking Yuespi Tang, administer 1.5 grains of Aspirin dissolved in white sugar water orally; this will surely induce sweating. While the patient is sweating, take Yuespi Tang; the sweating will increase significantly, and urination will subsequently flow smoothly.

Dr. XX from Japan used 10 grains of Mahuang, decocted in 100 grains of water, as a daily dose divided into three servings, to treat oliguria in chronic nephritis and oliguria due to renal atrophy. It was effective in some cases and ineffective in others, because the syndromes differed in cold/heat and deficiency/excess. He did not know how to use adjuvant herbs to fully utilize the strengths of Mahuang. Observe Yuespi Tang in the Water-Gas Chapter of *Jingui*: Mahuang is assisted by Shigao because the pulse is floating and heat is present (floating pulse indicates Wind, and there is indeed Heat). In Mahuang Fuzi Tang (Ephedra and Aconite Decoction), Mahuang is assisted by Fuzi (Aconiti Lateralis Radix Praeparata) because the pulse is deep and Cold is present. Through flexible modification, each change corresponds closely to the pathogenesis; this is truly someone who knows how to skillfully use Mahuang.

In ancient prescriptions containing Mahuang, Mahuang is first boiled for several boils, and the floating foam is blown away, then other herbs are added. This is presumably because the floating foam has overly fierce medicinal properties; removing it makes the nature of the herb peaceful.

Mahuang with nodes has a slightly weaker sweating-inducing power; removing the nodes makes the sweating-inducing power stronger. Currently, users mostly do not remove the nodes. As for Mahuang Gen (Ephedrae Radix et Rhizoma), it is purely a sweat-arresting agent. Although they come from the same plant, the properties of the root and stem are so vastly different. Without careful experimentation, how could one know this?

Lu Jiuzhi said: "Using a few qian of Mahuang can induce sweating; this applies to treating people in the South, but not those in the North. Because the climate in the South is warm, people's skin and muscles are thin, and sweat comes out most easily; hence the saying in the South that 'Mahuang should not exceed one qian.' In the North, especially beyond the Great Wall, the climate is cold, people's skin and muscles are thick and strong. If they also work outdoors laboriously, exposed to wind and frost, during severe cold weather, one often needs to use seven or eight qian to induce sweating. The way of using drugs values adapting to time, place, and individual, flexibly considering to overcome the disease as the primary goal, and should not be bound by preconceived notions."