东垣云∶“香港脚实由水湿，然有二焉。南方卑湿，清湿袭虚，则疾起于下，此是外感；北
方常食膻乳，又饮酒太过，脾胃有伤，不能运化，水湿下流，此内而至外者也。”
香港脚有干湿不同。如两胫肿大，名湿香港脚，是为壅疾，不宜骤补，宜鸡鸣散疏通其下，
不使其壅；若壅既成者，宜砭去恶血，然后服药，如两胫不肿，或顽痹、或挛急、或缓纵，
名干香港脚，宜四物汤加牛膝、木瓜、苍术、黄柏、肉桂、泽泻之类主之。二症虽不宜骤补，
而三阴受病，上气喘急，及上入少腹不仁，急宜八味丸补火以利水。外以矾石一两，酸浆水
一斗五升，煎三五沸浸之。丹溪以白芥子、白芷等分末，姜汁调敷之。
香港脚症，小腹顽痹不仁，不过三五日，即令呕吐，名香港脚入心，死症。
治香港脚入心，仲景用肾气丸通膀胱之气，安其肾水，不使攻心。巢氏用风引汤，取石性
易于下达，胜其湿热，不使攻心。二方皆为救危之神剂，一治肾气之虚，一治湿热之盛，宜
凭症择用之。
脉浮弦起于风，濡弱起于湿，洪数起于热，迟涩起于寒。沉而伏，毒在筋骨也；指下涩
涩不调，毒在血分也。夏暑脚膝冷痛，其脉阳濡阴弱，湿温也。香港脚多从暑湿得之。
问曰∶何故得者有冷有热？答曰∶足有三阴三阳。寒中三阳，所患必冷；暑中三阴，所
患必热，故有表里冷热。冷热不同，热者疗以冷药，冷者疗以热药。以意消息之，脾受阳毒
即热顽，肾受阴湿即寒痹。
李东垣说：“香港脚（脚气病）确实是由水湿引起的，但有两种情况。南方地势低洼潮湿，清冷湿气侵袭人体虚弱之处，疾病便从下部发起，这属于外感；北方人常食用膻腥乳制品，又饮酒过度，损伤脾胃，导致不能运化水湿，水湿向下流注，这是由内伤进而影响体表的。”
香港脚有干、湿两种不同性质。如果两小腿肿大，称为湿香港脚，这是一种壅滞之疾，不适宜立即进补，宜用鸡鸣散疏通下部，防止其壅滞；如果已经形成壅滞，宜用砭石刺破排出恶血，然后再服药；如果两小腿不肿，或者出现麻木疼痛、筋脉拘挛、或弛缓无力等症状，称为干香港脚，宜用四物汤加牛膝、木瓜、苍术、黄柏、肉桂、泽泻等药物为主进行治疗。这两种病症虽然都不宜立即进补，但如果三阴经受病，出现上气喘急，以及邪气上行至小腹导致麻木不仁，则急需使用八味丸（金匮肾气丸）温补肾阳以利水湿。外用方法是用矾石一两，酸浆水一斗五升，煎煮三五沸后浸泡患处。朱丹溪主张用白芥子、白芷各等分研成末，用姜汁调匀后敷贴。
香港脚病症中，如果小腹麻木不仁，不过三五天，就会引起呕吐，称为“香港脚入心”，这是死症。
治疗“香港脚入心”，张仲景使用肾气丸以通利膀胱之气，安定肾水，防止邪气攻心。巢元方使用风引汤，利用矿物药性易于下达的特点，克制湿热，防止邪气攻心。这两个方剂都是抢救危重症的神效方剂，一个治疗肾气虚，一个治疗湿热盛，应当根据症状选择使用。
脉象浮弦起于风邪，濡弱起于湿邪，洪数起于热邪，迟涩起于寒邪。脉象沉而伏匿，说明毒邪在筋骨；手指下感觉涩涩不调，说明毒邪在血分。夏季暑天脚膝冷痛，脉象阳部濡软、阴部微弱，这是湿温病。香港脚多因暑湿之邪所致。
问：为什么得病有的偏冷，有的偏热？答：足部有三阴经和三阳经。寒邪侵犯三阳经，所患疾病必定偏冷；暑邪侵犯三阴经，所患疾病必定偏热，所以有表里、冷热的区别。冷热不同，热证用寒凉药物治疗，冷证用温热药物治疗。需根据病情斟酌处理，脾受到阳毒侵袭就会变成热性的顽痹，肾受到阴湿侵袭就会变成寒性的痹证。
Li Dongyuan stated: "Hongxiangjiao (Gout/Jiaqi) is indeed caused by water-dampness, but there are two types. In the south, where the terrain is low and damp, clear-cold dampness invades the deficient areas, causing diseases to arise from below; this is an external contraction. In the north, people often consume mutton and dairy products and drink excessive alcohol, injuring the Spleen and Stomach, leading to an inability to transform and transport fluids; water-dampness flows downward, which is an internal injury manifesting externally."
Hongxiangjiao differs in dry and wet types. If both shins are swollen, it is called Wet Hongxiangjiao, a condition of obstruction/stagnation; sudden tonification is inappropriate. Instead, Jiming San should be used to unblock the lower body and prevent stagnation. If obstruction has already formed, bloodletting with bi-shi (stone needles) should be performed to remove evil blood before administering medicine. If the shins are not swollen, or if there is numbness and pain, tendon spasms, or flaccidity, it is called Dry Hongxiangjiao. It should be treated primarily with Siwu Tang (Four Substance Decoction) added with Niuxi (Achyranthes Root), Mugua (Chaenomeles Fruit), Cangzhu (Atractylodis Rhizoma), Huangbai (Phellodendri Cortex), Rougui (Cinnamon Bark), and Zexie (Alisma Rhizoma). Although neither type should be suddenly tonified, if the Three Yin meridians are affected, presenting with panting and shortness of breath, or ascending to the lower abdomen causing insensibility, Bawei Wan (Eight-Ingredient Pill / Jin Gui Shen Qi Wan) should be urgently administered to warm fire and promote diuresis. Externally, one liang of Fanshi (Alum) and fifteen sheng of sour bean curd juice are boiled for three to five boils for soaking. Zhu Danxi advocated using equal parts of Baijiezi (White Mustard Seed) and Baizhi (Angelicae Dahuricae Radix) ground into powder, mixed with ginger juice for application.
In Hongxiangjiao symptoms, if the lower abdomen is numb and insensible, vomiting may occur within three to five days. This is called "Hongxiangjiao entering the Heart," a fatal condition.
To treat "Hongxiangjiao entering the Heart," Zhang Zhongjing used Shenqi Wan (Kidney Qi Pill) to unblock Bladder Qi and stabilize Kidney Water, preventing the pathogen from attacking the Heart. Chao Yuanfang used Fengyin Tang (Wind-Guiding Decoction), utilizing the heavy nature of minerals to descend easily, overcoming damp-heat and preventing the pathogen from attacking the Heart. Both formulas are miraculous agents for saving critical conditions: one treats Kidney Qi deficiency, the other treats severe damp-heat. They should be selected based on symptoms.
A floating and wiry pulse arises from Wind; a soggy and weak pulse arises from Dampness; a surging and rapid pulse arises from Heat; a slow and choppy pulse arises from Cold. A deep and hidden pulse indicates toxin in the sinews and bones; a choppy and irregular sensation under the fingers indicates toxin in the Blood level. Cold pain in the feet and knees during summer heat, with a soggy Yang pulse and weak Yin pulse, indicates Damp-Warmth. Hongxiangjiao is mostly contracted from Summer-Heat and Dampness.
Question: Why do some cases present with Cold and others with Heat? Answer: The feet contain the Three Yin and Three Yang meridians. Cold invading the Three Yang meridians results in Cold disease; Summer-Heat invading the Three Yin meridians results in Heat disease. Thus, there are distinctions of interior/exterior and cold/heat. For different cold and heat patterns, Heat is treated with Cold medicines, and Cold is treated with Hot medicines. One must deliberate according to the situation: when the Spleen receives Yang toxin, it becomes a hot, stubborn Bi syndrome; when the Kidney receives Yin dampness, it becomes a cold Bi syndrome.