泻肝胆火，下焦湿热
大苦大寒，沉阴下行。益肝胆而泻火（相火寄于肝胆，有泻无补，泻其邪热，即所以补
火也），兼入膀胱、肾经。除下焦之湿热，与防己同功。酒浸亦能外行、上行。
治骨间寒热（肾主骨），惊痫邪气（肝经风火），时气温热，热痢疸黄、寒湿香港脚（足伤
湿热，则成香港脚。肿而痛者，为湿香港脚，宜清热利湿搜风。又有挛缩枯细，痛而不肿者，名
干香港脚，宜养血润燥），咽喉风热，赤睛 肉（泻肝胆火，能明目。元素曰∶柴胡为主，龙
胆为使，目疾要药。昂按∶若目疾初起，宜发散，忌用寒凉），痈疽疮疥。过服损胃。
甘草水浸一宿，曝用。小豆、贯众为使。忌地黄。
泻肝，散郁火
咸寒，色青泻肝。散五脏郁火，解中、下焦蓄蕴风热（《衍义》曰∶一妇患脐、腹、二
阴遍生湿疮，热痒而痛，出黄汁，二便涩。用鳗鲡、松脂、黄丹之类涂之，热痛愈甚。其妇
嗜酒，喜食鱼、虾发风之物。乃用马齿苋四两研烂，入青黛一两和涂，热痛皆去，仍服八正
散而愈。此中、下焦蓄蕴风热。毒瓦斯若不出，当作肠风、内痔。妇不能禁酒物，果仍发痔）
。
治伤寒发斑，吐咯血痢（阴虚火炎者忌用。合杏仁研，置柿饼中煨食，名圣饼子，治咯
血）。小儿惊痫，疳热丹热，敷痈疮、蛇犬毒。
即靛花。取娇碧者，水飞净用（内多锻石，故须淘净）。
【龙胆草】
清泻肝胆实火，清除下焦湿热。
药性大苦大寒，质地沉重且性沉降下行。能补益肝胆并清泻火热（相火寄居于肝胆，此经只有清泻而无滋补之法，清泻其邪热，即是补益相火），同时兼入膀胱经和肾经。能去除下焦的湿热，功效与防己相同。用酒浸泡后，也能向外、向上运行。
治疗骨节间的寒热往来（肾主骨），惊厥癫痫及邪气干扰（肝经风火所致），时行温热病，热毒痢疾、黄疸、寒湿导致的香港脚（足部损伤于湿热，则形成香港脚。肿胀疼痛的，称为湿香港脚，宜清热利湿搜风；又有拘挛收缩、枯瘦细小、疼痛但不肿胀的，称为干香港脚，宜养血润燥），咽喉风热，眼睛红赤有翳膜（清泻肝胆火，能明目。李东垣说：柴胡为主药，龙胆草为使药，是治疗眼疾的要药。汪昂按语：若眼疾初起，宜发散，忌用寒凉药物），痈疽疮疥。过量服用会损伤胃气。
用甘草水浸泡一夜，晒干后使用。以赤小豆、贯众为引经药。忌与地黄同用。
【青黛】
清泻肝火，疏散郁结之火。
味咸性寒，色青入肝而泻肝。能疏散五脏郁结之火，解除中焦、下焦蓄积蕴藏的风热（《本草衍义》记载：一位妇女患脐部、腹部、前后二阴遍生湿疮，发热瘙痒且疼痛，流出黄色汁液，大小便涩滞。用鳗鲡鱼、松脂、黄丹等涂抹，热痛反而加重。该妇女嗜酒，喜欢吃鱼、虾等发风之物。于是用四两马齿苋研烂，加入一两青黛调和涂抹，热痛全消，再服用八正散而痊愈。这是中、下焦蓄积蕴藏的风热。如果毒气不能排出，可能会发展为肠风或内痔。该妇女不能戒除酒肉，果然痔疮复发）。
治疗伤寒引起的发斑，吐血、咯血、痢血（阴虚火旺者忌用。与杏仁研细，放入柿饼中煨熟食用，名为圣饼子，治疗咯血）。小儿惊厥癫痫，疳积发热、丹毒发热，外敷治疗痈疮、蛇咬犬伤中毒。
青黛即靛蓝的花。选取颜色娇碧的，用水飞法洗净后使用（内部含有较多的锻石，所以必须淘洗干净）。
[Longdancao (Gentianae Radix)]
Purges Liver and Gallbladder fire, drains damp-heat from the Lower Jiao.
Extremely bitter and extremely cold in nature, heavy and sinking, moving downward. It benefits the Liver and Gallbladder while purging fire (Xianghuo [Ministerial Fire] resides in the Liver and Gallbladder; this organ system is treated by purging rather than tonifying; purging its pathogenic heat is equivalent to tonifying the fire), and also enters the Bladder and Kidney meridians. It eliminates damp-heat in the Lower Jiao, with effects similar to Fangji (Stephaniae Tetrandrae Radix). When soaked in wine, it can also move outward and upward.
Treats chills and fever between the bones (the Kidneys govern the bones), convulsions, epilepsy, and pathogenic influences (due to Wind-Fire in the Liver meridian), seasonal warm-heat diseases, heat-toxin dysentery, jaundice, and Hongjiaojiao [Hongjiaojiao refers to gout or rheumatic arthritis of the foot caused by damp-heat] (injury of the feet by damp-heat leads to Hongjiaojiao. Those that are swollen and painful are called Wet Hongjiaojiao, suitable for clearing heat, promoting urination to drain dampness, and searching out wind; those that are contracted, shriveled, thin, painful but not swollen are called Dry Hongjiaojiao, suitable for nourishing blood and moistening dryness), wind-heat in the throat, red eyes with nebula (purging Liver and Gallbladder fire can brighten the eyes. Li Dongyuan stated: Chaihu [Bupleuri Radix] as the chief herb, Longdancao as the assistant herb, is a key medicine for eye diseases. Wang Ang notes: If eye disease is in its initial stage, dispersal is indicated, and cold-cooling herbs should be avoided), carbuncles, ulcers, sores, and scabies. Overconsumption damages the Stomach Qi.
Soak in Licorice water (Gancao Shui) overnight, then dry in the sun. Use with Adzuki Bean (Xiaodou) and Zhuguanzhong (Zhuguanzhong Herba) as guiding herbs. Avoid using with Rehmannia Root (Dihuang).
[Qingdai (Indigo Naturalis)]
Purges the Liver, dissipates stagnant fire.
Salty and cold in nature, green in color, enters the Liver to purge it. It dissipates stagnant fire in the Five Viscera, and resolves Wind-Heat accumulated and harbored in the Middle and Lower Jiao (Bencao Yanyi records: A woman suffered from wet sores all over her umbilicus, abdomen, and both yin organs, with heat, itching, pain, and discharge of yellow fluid, along with difficult urination and defecation. She applied Eel [Manli], Pine Resin [Songzhi], and Red Lead [Huandan], but the heat and pain worsened. The woman was fond of alcohol and liked to eat fish and shrimp, which are wind-inducing foods. Therefore, four taels of Purslane [Machixian] were mashed, mixed with one tael of Qingdai, and applied topically. The heat and pain disappeared completely, and she recovered after taking Baze San [Eight-Positive Powder]. This indicates Wind-Heat accumulated in the Middle and Lower Jiao. If the toxic qi does not exit, it may develop into Changfeng [Intestinal Wind] or internal hemorrhoids. The woman could not abstain from alcohol and food, and indeed her hemorrhoids recurred).
Treats macules caused by Cold Damage (Shanghan), hematemesis, hemoptysis, and bloody dysentery (Contraindicated in cases of Yin deficiency with flaming fire. Mix with Almond [Xingren], place inside a persimmon cake, bake, and eat; named Shengbingzi [Holy Cake], treats hemoptysis). Treats pediatric convulsions and epilepsy, malnutrition fever, erysipelas fever; apply topically for carbuncles, sores, snake bites, and dog bite toxins.
Qingdai is the flower of Indigofera tinctoria. Select those with a delicate blue-green color, wash cleanly using the water-flying method (it contains much calcined stone, so it must be washed clean).