夫岭南青草、黄芒瘴，犹如岭北伤寒也。南地暖，故太阴之时，草木不黄落，伏蛰不闭
藏，杂毒因暖而生。故岭南从仲春讫仲夏，行青草瘴，季夏讫孟冬，行黄芒瘴。量其用药体
性，岭南伤寒，但节气多温，冷药小寒于岭北。时用热药，亦减其锱铢，三分去二。但此病
外候小迟，因经络之所传，与伤寒不异。然阴阳受病，会同表里，须明识患源，不得妄攻汤
艾。假令宿患痼热，今得瘴毒，毒得热更烦，虽形候正盛，犹在于表，未入肠胃，不妨温而
汗之。已入内者，不妨平而下之。假令本有冷，今得温瘴，虽暴壮热烦满，视寒正须温药汗
之，汗之不歇，不妨寒药下之。夫下利治病等药在下品，药性凶毒，专主攻击，不可恒服，
疾去即止。病若日数未入于内，不可预服利药，药尽胃虚，病必乘虚而进。此不可轻治。治
不瘥，成黄胆；黄胆不瘥，为尸疸。尸疸疾者，岭南中瘴气，土人连历不瘥，变成此病，不
须治也。岭北客人，犹得斟酌救之。病前热而后寒者，发于阳；无热而恶寒者，发于阴。发
于阳者，攻其外；发于阴者，攻其内。其一日、二日，瘴气在皮肤之间，故病者头痛恶寒，
腰背强重。若寒气在表，发汗及针必愈。三日以上，气浮于上，填塞心胸，使头痛胸满而闷
，宜以吐药，吐之必愈。五日以上，瘴气深结在脏腑，故腹胀身重，骨节烦疼，当下之。或
人得病久，方告医，医知病深，病已成结，非可发表解肌，所当问病之得病本末，投药可专
根据次第也。
The Qingcao (Green Grass) miasma and Huangmang (Yellow Husk) miasma in the Lingnan region are analogous to Shanghan (Cold Damage) in the regions north of the Nanling Mountains. The southern climate is warm; therefore, during the period governed by Taiyin (Taiyin Meridian/Pattern), vegetation does not wither and fall, and hibernating creatures do not seal themselves away for storage. Various toxic pathogens arise due to the warmth. Consequently, from Zhongchun (Mid-Spring) to Zhongxia (Mid-Summer), Qingcao miasma prevails in Lingnan; from Jixia (Late Summer) to Mengdong (Early Winter), Huangmang miasma prevails. Assessing the nature and properties of medicinal substances, the Shanghan in Lingnan differs only in that the solar terms are generally warmer, making cold-natured medicines slightly less potent than those used north of the mountains. When using hot-natured medicines, their dosage should also be reduced by two-thirds. Although the external manifestations of this disease appear slightly delayed, its transmission through the meridians is no different from Shanghan. However, whether the disease affects Yin or Yang, it involves both exterior and interior aspects. One must clearly identify the source of the illness and must not blindly administer decoctions or moxibustion. Suppose a patient has a chronic latent heat condition and subsequently contracts miasma toxicity; the toxicity combined with heat causes greater restlessness. Even if the physical symptoms appear vigorous, as long as the pathogen remains on the exterior and has not entered the stomach and intestines, it is permissible to use warm methods to induce sweating. If the pathogen has already entered the interior, it is permissible to use mild purgatives. Suppose a patient originally has a cold constitution and now contracts warm miasma; although they suddenly present with high fever, irritability, and distension/fullness, observing the signs indicates a need for warm medicines to induce sweating. If sweating does not resolve the condition, it is permissible to use cold-natured purgatives. Medicines belonging to the category of purgation are listed in the lower grade; their properties are fierce and toxic, specifically intended for attacking pathogens, and they must not be taken continuously. Discontinue use once the disease is eliminated. If the number of days since onset is short and the pathogen has not entered the interior, one must not pre-emptively administer purgative medicines. Exhausting the medicine will weaken the stomach Qi, allowing the disease to advance by taking advantage of the deficiency. This condition must not be treated lightly. If treatment fails, it develops into Huangdan (Jaundice); if Jaundice treatment fails, it becomes Shidan (Corpse Jaundice). Shidan refers to a condition where people in Lingnan contract miasma qi, and despite repeated local treatments, they do not recover, eventually developing this disease. It requires no treatment. Guests from north of the mountains may still be treated with careful judgment. Those who experience fever first followed by aversion to cold manifest from Yang; those who have no fever but only aversion to cold manifest from Yin. For those manifesting from Yang, attack the exterior; for those manifesting from Yin, attack the interior. On the first or second day, the miasma qi resides between the skin and muscles, causing headache, aversion to cold, and stiffness/heaviness in the waist and back. If cold qi is on the exterior, recovery will surely follow sweating therapy and acupuncture. After three days, the qi floats upward, filling and obstructing the chest and heart, causing headache, chest fullness, and oppression. It is appropriate to use emetic medicines; vomiting will surely lead to recovery. After five days, the miasma qi deeply knots within the zang-fu organs, causing abdominal distension, heaviness of the body, and painful movement of the bone joints. Purgation should be employed. In cases where patients delay seeking medical advice until late in the course of the disease, and the physician recognizes that the pathogen is deep and the condition has formed a knot, exterior-releasing and muscle-loosening methods are inappropriate. Instead, one should inquire about the origin and progression of the illness and administer medicines strictly according to the sequential stages of the disease.