卫生方云。麻黄生于中牟。有麻黄之地。冬雪不积。盖麻黄能泄外阳故也。今南方无霜雪。皆
如麻黄之地。阳气恒泄。即此可知。人居其间。不劳麻黄而自汗。有病则不宜轻发汗。轻用麻黄。
此理甚明。前辈诗云。四时恒是夏。一雨便成秋。读此一联。不惟知南方天气。亦可触类而知。
夫人之病也。假如病者多热。才经一汗。便翻然为冷。是岂宜轻发汗耶。如五积散。通关散。金沸草散。九
宝饮。小续命汤。十神汤。香苏散。俱有麻黄。虽有主对。亦不可服。若麻黄汤。青龙汤。南方
尤不可遽用也。今人例以麻黄为发散药。殊不知其力只能驱我
之内阳。以劫外寒也。古今方书用肺经咳嗽。以肺之性恶寒。肺为娇脏。易于感寒。乃宜用之。
仲景治足太阳伤寒。以太阳在表。非汗不解。及治少阴经伤寒。发热脉沉。盖少阴当无热恶
寒反发热者。邪在表也。故以温剂佐之。发中有补。皆所当用也。除此三经。方书已自少用。况
南方不寒之地。瘴气交重。瘴病岂尽因感寒耶。不因感寒。不用麻黄。又何不可。南史记范云欲赴
梁武帝九锡之命。忽尔伤寒。召医徐文伯治之。恐不得与庆事。实告之曰。欲即愈。当先期取汗。
但不免妄泄元阳。恐二年后不复起矣。云曰朝闻夕可。况二年乎。文伯烧地布席。置云于上。得汗
而解。云大喜。文伯曰。不足喜也。后二年果应。夫发汗先期。尚促寿限。况不当汗而汗乎。
又尝见有染瘴者。上热下寒。腰足寒痛。自谓五积散症也。遂倍加麻黄。多衣覆汗。竟成重症。
虽服真武汤。亦莫能救。并赘于此。为妄用药者之戒。大凡瘴病误用麻黄。服后哑者。七日内死。
或筋惕肉 者。十四日内死。或目赤上气喘促者。十四日内死。若汗出不止。脉细如无悸动。寒
战发哕者。实时死。余常目击。可不慎哉。
《卫生方》记载：麻黄生长在中牟地区。凡是生长麻黄的地方，冬天的积雪不会堆积。这是因为麻黄能够发散体表的阳气。如今南方没有霜雪，都像生长麻黄的地方一样，阳气经常处于发散状态。由此可以推知，人们居住在这样的环境中，不需要使用麻黄也会自然出汗。一旦生病，就不宜轻易使用发汗法。轻率地使用麻黄，其中的道理是非常明白的。前辈诗人写道：“四季总是像夏天，一场雨就变成秋天。”读这一联诗句，不仅知道南方的气候特点，也可以触类旁通地理解其他事物。
人的疾病，假如患者体内多有热邪，刚刚经过一次发汗，病情就会突然转变为寒证。这哪里是适宜轻易发汗的呢？像五积散、通关散、金沸草散、九宝饮、小续命汤、十神汤、香苏散这些方剂，都含有麻黄。虽然它们有各自的主治对症，但在南方也不可以服用。至于麻黄汤、青龙汤，在南方更是不可贸然使用。现在的人习惯把麻黄当作发散药，却不知道它的力量只能驱散我体内的阳气，以强行解除外来的寒邪。古今方书中治疗肺经咳嗽，因为肺的特性厌恶寒冷，肺是娇嫩的脏器，容易感受寒邪，这才适宜使用麻黄。
张仲景治疗足太阳伤寒，是因为太阳经位于体表，非发汗不能解表；以及治疗少阴经伤寒，出现发热但脉象沉细。通常少阴病应当是无热恶寒，如果出现反常发热，说明邪气仍在体表。所以用温补的药物辅助，发汗中兼有补益作用，这些都是应当使用的。除了这三条经络，方书中已经很少使用麻黄了，何况南方是不寒冷的地方，瘴气交加重浊，瘴病难道都是因感受寒邪引起的吗？如果不是因感受寒邪，不使用麻黄，又有什么不可以的呢？
《南史》记载范云想要接受梁武帝授予的“九锡”之命时，忽然得了伤寒。召请医生徐文伯诊治，担心不能赶上庆贺之事。徐文伯如实告诉他：“要想立即痊愈，应当先期取汗，但这难免会妄泄元阳，恐怕两年后就不能再起来了。”范云说：“早上听到真理晚上死去都可以，何况只是两年呢？”徐文伯烧暖地面铺上席子，让范云躺在上面，出汗后病就好了。范云非常高兴。徐文伯说：“这不值得高兴，两年后果然应验了。”既然提前发汗尚且缩短寿命，何况是不当发汗而发汗呢？
我又曾经见过感染瘴气的人，表现为上热下寒，腰部和脚部寒冷疼痛，自认为是五积散的病症，于是加倍加入麻黄，多穿衣服覆盖以求出汗，最终导致重症。虽然服用了真武汤，也无法挽救。把这些情况附加在这里，作为乱用药物的警戒。大凡瘴病患者误用麻黄，服药后出现失音（哑）的，七日内死亡；或者出现筋肉跳动（筋惕肉瞤）的，十四日内死亡；或者出现眼睛发红、上气喘促的，十四日内死亡。如果汗出不止，脉象细微好像没有悸动，伴有寒战和呃逆的，当时就会死亡。我常常亲眼目睹这些情况，能不谨慎吗？
The *Weisheng Fang* (Prescriptions for Health Preservation) states: Ephedrae Herba (Mahuang, 麻黄) grows in Zhongmu. In places where Ephedra grows, winter snow does not accumulate. This is because Ephedra can disperse the external Yang Qi (vital energy on the body surface). Currently, the southern regions have no frost or snow, resembling areas where Ephedra grows; thus, Yang Qi is constantly dispersed. From this, it can be inferred that people living there sweat naturally without using Ephedra. When illness occurs, one should not lightly employ diaphoresis (sweating therapy). The use of Ephedra must be approached with caution, as the reasoning is clear. An ancient poem states: "Four seasons are always like summer; a single rain turns it to autumn." Reading this couplet allows one not only to understand the southern climate but also to apply this logic to other matters.
Regarding human diseases, if a patient has excessive internal heat, a single episode of sweating may suddenly cause the condition to shift to cold. How could light diaphoresis be appropriate here? Formulas such as Wuji San (Five Accumulations Powder), Tongguan San (Passage Through Obstruction Powder), Jinfeicao San (Boiling Grass Powder), Jiubao Yin (Nine Treasures Drink), Xiao Xuming Tang (Minor Continuation of Life Decoction), Shishen Tang (Ten Spirits Decoction), and Xiangsu San (Aromatic Su Decoction) all contain Ephedra. Although they have specific indications, they should not be taken in the south. Furthermore, Mahuang Tang (Ephedra Decoction) and Qinglong Tang (Azure Dragon Decoction) should especially not be used hastily in the south. People today habitually regard Ephedra as a dispersing herb, unaware that its power merely drives away internal Yang Qi to forcibly overcome external cold. In ancient and modern formularies, Ephedra is indicated for lung meridian coughs because the Lung organ dislikes cold and is delicate, making it susceptible to cold pathogens.
Zhang Zhongjing treated Taiyang (Greater Yang) exogenous cold by inducing sweating, as the Taiyang channel is at the exterior and requires sweating to resolve. He also treated Shaoyin (Lesser Yin) exogenous cold presenting with fever and a deep pulse. Typically, Shaoyin disease involves aversion to cold without fever; if fever is present, it indicates the pathogen is still at the exterior. Therefore, warm tonifying agents are used as assistants, achieving sweating while providing tonification; these are appropriate uses. Apart from these three channels, formularies rarely use Ephedra. Moreover, in the non-cold southern regions where miasma (pathogenic environmental factors) is heavy, is miasmatic disease entirely caused by cold contraction? If not caused by cold, why is it inappropriate to avoid Ephedra?
The *History of the Southern Dynasties* records that Fan Yun, upon accepting the Nine Bestowals from Emperor Wu of Liang, suddenly contracted exogenous cold. He summoned physician Xu Wenbo for treatment, fearing he would miss the celebration. Xu Wenbo truthfully stated: "To recover immediately, sweating must be induced beforehand, but this will recklessly deplete Yuan Yang (Primordial Yang), and you likely will not survive two years." Fan Yun replied: "If I hear the Way in the morning, I am content to die in the evening; what more about two years?" Xu Wenbo heated the floor, laid mats, and placed Fan Yun upon them. After sweating, the illness resolved. Fan Yun was greatly delighted. Xu Wenbo said: "There is no need to rejoice; indeed, two years later, it came to pass." Since premature sweating shortens life expectancy, how much more so is it harmful when sweating is contraindicated?
I have also seen cases of those infected with miasma presenting with upper heat and lower cold, with cold pain in the waist and feet. They mistakenly identified this as a Wuji San pattern and doubled the dose of Ephedra, covering themselves heavily to induce sweating, which ultimately resulted in severe illness. Even the administration of Zhenwu Tang (True Warrior Decoction) could not save them. These cases are recorded here as a warning against reckless medication. Generally, if miasmatic patients misuse Ephedra and develop aphonia (loss of voice), death occurs within seven days. If muscle twitching (fasciculation) occurs, death occurs within fourteen days. If red eyes, upward gasping, and rapid breathing occur, death occurs within fourteen days. If sweating continues unceasingly, the pulse becomes minute and faint as if absent, accompanied by chills and hiccups, death occurs immediately. I have witnessed these situations personally; how can one not be cautious?