通，行水，泻下焦血分湿热
大苦大寒（《本经》）平，《别录》温）。太阳（膀胱）经药。能行十二经，通腠理，利九
窍，泻下焦血分湿热，为疗风水之要药。
治肺气喘嗽（水湿），热气诸痫（降气下痰），湿症香港脚（足伤寒湿为香港脚。寒湿郁而为
热，湿则肿，热则痛。防己为主药。湿加苡仁、苍术、木瓜、木通，热加芩、柏，风加羌活、
萆，痰加竹沥、南星，痛加香附、木香，活血加四物，大便秘加桃仁、红花，小便秘加牛
膝、泽泻，痛连臂加桂枝、威灵仙，痛连胁加胆草。又有足跟痛者，属肾虚。不与香港脚同论
），水肿风肿，痈肿恶疮。或湿热流入十二经，致二阴不通者，非此不可。然性险而健，阴
虚及湿热在上焦气分者禁用（《十剂》曰∶通可去滞，通草防己之属是也。通草即木通，是
徐之才亦以行水者，为通与燥剂无以别矣。木通甘淡，泻气分湿热；防己苦寒，泻血分湿热
。本集以行水为通剂，改热药为燥剂）。
出汉中，根大而虚通，心有花纹，色黄，名汉防己；黑点黄腥木强者，名木防己，不佳
（陈藏器曰∶治风用木防己，治水用汉防己）。酒洗用。恶细辛。畏萆 。
大泻气秘，通，行水
辛苦大寒。属火性急，大能下气，行膀胱水。肿中水气 急者，非此不能除。破积聚症
结，伏留热气，消肿除痰，止嗽定喘（水湿泛溢，为肿胀，为痰嗽，为喘满）通经利便。久
服令人虚（《十剂》曰∶泄可去闭，葶苈、大黄之属是也。大黄泄阴分血闭，葶苈泄阳分气
闭，气味俱浓，不减大黄。然有甜、苦二种，甜者性缓，苦者性急，泄肺而伤胃，宜大枣辅
之。仲景有葶苈大枣泻肺汤，治肺气喘急不得卧。昂按∶辅以大枣，补土所以制水）。
子如黍米，微长色黄。合糯米微炒，去米用。得酒良。榆皮为使。
防己：具有通利、行水、泻除下焦血分湿热的功效。
其性大苦大寒（《神农本草经》记载为平性，《名医别录》记载为温性）。归太阳（膀胱）经。能通行十二经脉，疏通腠理，通利九窍，泻除下焦血分湿热，是治疗风水病的重要药物。
用于治疗肺气喘嗽（由水湿引起）、热气诸痫（降气下痰）、湿症香港脚（足部受伤寒湿导致香港脚。寒湿郁结化为热，湿盛则肿，热盛则痛。防己为主药。若兼湿加薏苡仁、苍术、木瓜、木通；兼热加黄芩、黄柏；兼风加羌活、萆薢；兼痰加竹沥、天南星；疼痛加香附、木香；需活血加四物汤；大便秘结加桃仁、红花；小便不利加牛膝、泽泻；疼痛牵连手臂加桂枝、威灵仙；疼痛牵连胁肋加龙胆草。另有足跟痛者，属肾虚，不与香港脚同论），水肿、风肿、痈肿恶疮。若是湿热流入十二经脉，导致前后二阴不通的，非用此药不可。然而其性质险峻且作用猛烈，阴虚及湿热在上焦气分的患者禁用（《十剂》说：通法可以去除滞塞，通草、防己之类属于此类。通草即木通，徐之才也将行水药视为通剂与燥剂没有区别。木通甘淡，泻气分湿热；防己苦寒，泻血分湿热。本集将行水药列为通剂，将热药改为燥剂）。
产于汉中，根大而中空，心有花纹，色黄，名为汉防己；有黑点、味黄腥、木质强者，名为木防己，品质不佳（陈藏器说：治风用木防己，治水用汉防己）。需用酒洗后使用。畏细辛，恶萆薢。
葶苈子：具有大泻气秘、通利、行水的功效。
其性辛苦大寒。属火，性急，能强力下气，行膀胱之水。对于肿胀中水气急迫的情况，非此药不能消除。能破除积聚症结，清除伏留的热气，消肿除痰，止咳定喘（水湿泛溢，导致肿胀、痰嗽、喘满），通经利便。久服使人虚弱（《十剂》说：泄法可以去除闭阻，葶苈子、大黄之类属于此类。大黄泄阴分血闭，葶苈子泄阳分气闭，气味浓厚，不亚于大黄。但有甜、苦两种，甜的性缓，苦的性急，泻肺气而伤胃气，宜用大枣辅助。张仲景有葶苈大枣泻肺汤，治疗肺气喘急不得卧。汪昂按语：辅以大枣，补益脾胃所以能制约水邪）。
种子如黍米大小，略长，色黄。与糯米微炒，去米后用。得酒制效果良好。榆皮为其使药。
Fangji (Stephaniae Tetrandrae Rhizoma): Possesses the functions of promoting unobstructed flow, moving water, and draining damp-heat from the blood level of the lower jiao.
Its nature is extremely bitter and cold (recorded as neutral in *Shennong Bencao Jing*, warm in *Mingyi Bielu*). It enters the Taiyang (Bladder) meridian. It can circulate through the twelve meridians, open the interstices (cou li), benefit the nine orifices, drain damp-heat from the blood level of the lower jiao, and serves as a key herb for treating Fengshui (wind-water edema).
It treats lung asthma and cough (caused by water-dampness), various epilepsy cases due to heat qi (by descending qi and phlegm), and wet-type Hongjiaojiao (foot gout caused by cold-dampness invading the foot. Cold-dampness stagnates and transforms into heat; dampness causes swelling, heat causes pain. Fangji is the principal herb. If accompanied by dampness, add Yiyiren, Cangzhu, Mugua, Mutong; if accompanied by heat, add Huangqin, Huangbai; if accompanied by wind, add Qianghuo, Bixie; if accompanied by phlegm, add Zhuli, Nanting; if painful, add Xiangfu, Muxiang; if blood stasis requires invigoration, add Siwu Tang; if constipation occurs, add Taoren, Honghua; if dysuria occurs, add Niuxi, Zexie; if pain radiates to the arm, add Guizhi, Weilingxian; if pain radiates to the hypochondrium, add Longdancao. For heel pain due to Kidney deficiency, it is not discussed together with Hongjiaojiao), edema, wind-edema, carbuncles, sores, and malignant ulcers. If damp-heat flows into the twelve meridians causing obstruction of the two yin openings (urethra and anus), this herb is indispensable. However, its nature is perilous and vigorous; it is contraindicated for patients with Yin deficiency and those with damp-heat in the Qi level of the upper jiao (*Ten Formulas* states: Unblocking methods remove stagnation, such as Tongcao and Fangji. Tongcao is Mutong; Xu Zhicai also classified diuretics as unblocking agents indistinguishable from drying agents. Mutong is sweet and bland, draining damp-heat from the Qi level; Fangji is bitter and cold, draining damp-heat from the blood level. This collection classifies diuretics as unblocking agents and heat-clearing herbs as drying agents).
Produced in Hanzhong, the root is large and hollow inside with floral patterns in the center, yellow in color, named Hanfangji; those with black spots, yellowish-fishy smell, and strong woody texture are named Mufangji, which are of inferior quality (Chen Cangqi stated: Use Mufangji for wind disorders, Hanfangji for water disorders). Use after wine washing. It is incompatible with Xixin and fears Bixie.
Tinglizi (Descurainiae Semen / Lepidii Semen): Possesses the functions of strongly purging Qi stagnation/constipation, promoting unobstructed flow, and moving water.
Its nature is pungent, bitter, and extremely cold. It belongs to Fire, has an urgent nature, and can powerfully descend Qi and move water in the Bladder. For conditions of edema with urgent accumulation of water qi, only this herb can eliminate it. It breaks up accumulations and masses, clears latent heat qi, reduces swelling, eliminates phlegm, stops cough, and calms asthma (water-dampness overflowing leads to swelling, phlegm-cough, and wheezing/fullness), promotes menstruation, and benefits urination. Long-term use causes debility (*Ten Formulas* states: Purging methods remove closure, such as Tinglizi and Dahuang. Dahuang purges blood closure in the Yin level; Tinglizi purges Qi closure in the Yang level. Both have potent flavors and potency, comparable to Dahuang. There are sweet and bitter varieties; the sweet variety acts gently, the bitter variety acts urgently. It purges Lung Qi but damages Stomach Qi, so it should be assisted with Dazao. Zhang Zhongjing formulated Tinglizi Dazao Xiefei Tang to treat lung asthma and急促 breathing preventing lying down. Wang Ang notes: Assisting with Dazao tonifies Earth to control Water).
The seeds are like millet grains, slightly elongated, yellow in color. Lightly stir-fry with glutinous rice, discard the rice, and use the seeds. Processing with wine is beneficial. Yu Pi (Ulmus Cortex) is the guiding herb.