宣，发表，祛风，散湿
辛散风，温除湿，芳香通窍而表汗。行手足阳明（大肠、胃），入手太阴（肺，色白味
辛，故入肺），而为阳明主药（阳明之脉营于面，故治头面诸疾）。治阳明头目昏痛（杨吉老
方，白芷汤泡四、五遍，蜜丸弹子大，名都梁丸。每服一丸，荆芥点醋茶嚼下。杨吉老，名
介，治王定国病时在都梁，因以名丸），眉棱骨痛（风热与痰，同酒浸黄芩为末，茶下）牙
痛（上龈属足阳明，下龈属手阳明，二经风热）鼻渊（肺主鼻，风热乘肺，上烁于脑，故鼻
多浊涕而渊。经曰∶脑渗为涕，宜同细辛、辛夷治之），目痒泪出，面 （干去声，面黑气）
瘢疵（可作面脂），皮肤燥痒，三经风热之病。及血崩血闭，肠风痔 ，痈疽疮疡，三经湿
热之病。
活血排脓（肠有败脓血，淋露腥秽，致脐腹冷痛，须此排之），生肌止痛，解砒毒、蛇
伤（先以绳扎伤处，酒调下白芷末五钱。种白芷，能辟蛇）。又治产后伤风，血虚头痛（自
鱼尾上攻，多在日晚，宜四物加辛、芷。如气虚头痛，多在清晨，宜芎、 倍参、 。保寿
堂治正、偏头痛，白芷、川芎各三钱，搽牛脑上，加酒顿熟，热食尽醉，其病如失。鱼尾，
目之上角）。然其性升散，血热有虚火者禁用。
色白、气香者佳，或微炒用。当归为使。恶旋复花。
白芷，具有宣散、发表、祛风、除湿的功效。其味辛能发散风邪，性温能祛除湿气，气味芳香能通利孔窍并促使出汗。它主要作用于手足阳明经（大肠经和胃经），兼入足太阴肺经（因白色入肺，辛味亦入肺），因此是阳明经的主药（因为阳明经脉在面部循行，所以能治疗头面部的各种疾病）。
用于治疗阳明经引起的头目昏痛（杨吉老的方子：将白芷汤泡四到五遍，制成蜜丸如弹子大小，名为都梁丸。每次服用一丸，用荆芥蘸醋茶嚼服。杨吉老名介，他在都梁治疗王定国的病时创制此方，故以地名命名药丸）；眉棱骨痛（由风热与痰湿引起，可将黄芩用酒浸泡后研末，茶水送服）；牙痛（上牙龈属足阳明经，下牙龈属手阳明经，多因二经风热所致）；鼻渊（肺主鼻，风热侵袭肺部，向上熏蒸脑部，导致鼻涕浑浊且源源不断。医经说：“脑液渗漏为涕”，宜配合细辛、辛夷治疗）；眼睛发痒流泪；面色晦暗无光泽及面部斑点瑕疵（可制作成面部护肤脂）；皮肤干燥瘙痒。这些都属于三经（手足阳明及肺经）风热引起的病症。
此外，还能治疗血崩、经闭，以及肠风痔漏、痈疽疮疡，这些属于三经湿热引起的病症。
白芷能活血排脓（肠道内有腐败的脓血，淋漓腥臭，导致脐腹冷痛，需用此药排出脓血）；生肌止痛；解砒霜毒、蛇咬伤（先用绳子扎紧伤口处，用酒调服白芷末五钱。种植白芷，能驱避蛇类）。又用于治疗产后伤风，血虚头痛（疼痛从眼角上方攻冲，多在傍晚发作，宜用四物汤加川芎、白芷。如果是气虚头痛，多在清晨发作，宜用川芎、当归加倍人参、黄芪）。保寿堂治疗正头痛和偏头痛，用白芷、川芎各三钱，涂抹在牛脑上，加酒煮熟，趁热吃完直至醉倒，病即可痊愈。（鱼尾，指眼角的上方）。
Bai Zhi (Angelicae Dahuricae Radix) possesses the properties of dispersing, releasing the exterior, expelling wind, and dissipating dampness. Its pungent flavor disperses wind pathogens, its warm nature removes dampness, and its aromatic fragrance opens orifices and induces sweating. It enters the Hand-Yangming Large Intestine Meridian and Foot-Yangming Stomach Meridian, and also enters the Foot-Taiyin Lung Meridian (as white color and pungent flavor correspond to the Lung), making it a principal herb for the Yangming meridians (since the Yangming meridians circulate around the face, it treats various diseases of the head and face).
It treats dizziness and pain in the head and eyes caused by Yangming meridian disorders (Prescription by Yang Jilao: Soak Bai Zhi in decoction four or five times, form into honey pills the size of a bullet, named Duliang Wan. Take one pill per dose, chew with Jingjie [Schizonepetae Herba] dipped in vinegar-tea. Yang Jilao, whose name was Jie, created this prescription while treating Wang Dingguo's illness in Duliang, hence naming the pill after the place). It treats pain in the supraorbital ridge (caused by wind-heat and phlegm; mix Huangqin [Scutellariae Radix] soaked in wine into powder, take with tea). It treats toothache (the upper gum belongs to the Foot-Yangming Meridian, the lower gum to the Hand-Yangming Meridian; both are affected by wind-heat). It treats Bi Yuan (Nasal Polyps/Chronic Rhinitis) (The Lung governs the nose; wind-heat invading the Lung steams upward to the brain, causing profuse turbid nasal discharge. The Classics state: "Brain fluid seeps out as nasal mucus"; treat with Xixin [Asari Radix et Rhizoma] and Xinyi [Magnoliae Flos]). It treats itchy eyes with tearing, dark complexion (Mian Hei Qi), and facial blemishes (can be used as facial cream). These are conditions of wind-heat affecting the three meridians (Hand-Yangming, Foot-Yangming, and Lung).
Furthermore, it treats sudden uterine bleeding (Xue Beng) and amenorrhea (Xue Bi), intestinal wind with hemorrhoids (Chang Feng Zhi Lou), carbuncles, sores, and ulcers, which are conditions of damp-heat in the three meridians.
It invigorates blood and drains pus (when putrid blood and pus accumulate in the intestines, dripping foul-smelling fluids causing cold pain in the umbilical and abdominal regions, this herb is required to drain them); promotes tissue regeneration and relieves pain; resolves arsenic poisoning and snake bites (first tie a rope tightly around the wound site, then take 5 qian of Bai Zhi powder mixed with wine. Planting Bai Zhi can repel snakes). It also treats postpartum wind-stroke and headache due to blood deficiency (pain attacks from the outer corner of the eye upwards, usually occurring in the late afternoon; use Siwu Tang [Four Substances Decoction] plus Chuanxiong [Ligustici Chuanxiong Rhizoma] and Bai Zhi. If the headache is due to Qi deficiency, it usually occurs in the early morning; use Chuanxiong and Danggui [Angelicae Sinensis Radix] with doubled Renshen [Ginseng Radix] and Huangqi [Astragali Radix]. Baoshou Hall treats frontal and lateral headaches by mixing 3 qian each of Bai Zhi and Chuanxiong, applying them to cow brain, cooking with wine until done, eating hot until drunk, resulting in complete cure. "Yuwei" refers to the upper outer corner of the eye).
However, since its nature is ascending and dispersing, it is contraindicated for patients with blood-heat and deficient fire.
Those that are white in color and fragrant in aroma are superior; they may be slightly stir-fried before use. Danggui [Angelicae Sinensis Radix] serves as an guiding herb. It is incompatible with Xuanfuhua [Inulae Flos].