一、用散者，散表证也。观仲景太阳证用麻黄汤，阳明证用升麻葛根汤，少阳证用小柴
胡汤，此散表之准绳也。后世宗之，而复不能用之，在不得其意耳。盖麻黄之气，峻利而勇
。凡太阳经阴邪在表者，寒毒既深，非此不达，故制用此方，非谓太阳经药必须麻黄也。设
以麻黄治阳明、少阳之证，亦寒无不散，第恐性力太过，必反伤其气，岂谓某经某药必不可
移易，亦不过分其轻重耳。故如阳明之升麻、干葛，未有不走太阳、少阳者。少阳之柴胡，
亦未有不入太阳、阳明者。但用散之法，当知性力缓急，及气味寒温之辨，用得其宜，诸经
无不妙也。如麻黄、桂枝，峻散者也；防风、荆芥、紫苏，平散者也；细辛、白芷、生姜，
温散者也；柴胡、干葛、薄荷，凉散者也；羌活、苍术，能走经去湿而散者也；升麻、川芎
，能举陷上行而散者也。第邪浅者，忌峻利之属；气弱者，忌雄悍之属；热多者，忌温燥之
属；寒多者，忌清凉之属。凡热渴烦躁者喜干葛，而呕恶者忌之；寒热往来者宜柴胡，而泄
泻者忌之；寒邪在上者，宜升麻、川芎，而内热炎升者忌之。此性用之宜忌，所当辨也。至
于相配之法，则尤当知要，凡以平兼清，自成凉散；以平兼暖，亦可温经；宜大温者，以热
济热；宜大凉者，以寒济寒。此其运用之权，则毫厘进退，自有伸缩之妙，又何必胶柱刻舟
，以限无穷之病变哉！此无他，在不知仲景之意耳。
一、使用散剂（解表药），是为了疏散表证。观察张仲景治疗太阳病（太阳经受邪所致的病证）用麻黄汤，阳明病（阳明经受邪所致的病证）用升麻葛根汤，少阳病（少阳经受邪所致的病证）用小柴胡汤，这是疏散表证的准则。后世医家遵循这一原则，却又不能灵活运用，原因在于没有领会其真意。
麻黄的药性峻猛、通利且勇烈。凡是太阳经有阴寒之邪在体表的情况，寒毒已经深入，非用此药不能通达，所以制定这个方子，并不是说太阳经的病必须用麻黄。假如用麻黄来治疗阳明病、少阳病的证候，寒气同样可以消散，只是担心药性力量太过，必然反而损伤正气，难道是说某经的病某味药就绝对不可移动更换吗？也不过是区分轻重程度罢了。所以像阳明病用的升麻、干葛，没有不走向太阳经、少阳经的；少阳病用的柴胡，也没有不进入太阳经、阳明经的。
但是使用疏散的方法，应当知道药性的缓急，以及气味的寒温区别，用得恰当，各经的治疗都能取得妙效。比如麻黄、桂枝，属于峻猛的疏散药；防风、荆芥、紫苏，属于平和的疏散药；细辛、白芷、生姜，属于温性的疏散药；柴胡、干葛、薄荷，属于凉性的疏散药；羌活、苍术，能走窜经络、祛湿并疏散邪气的药；升麻、川芎，能提升下陷之气上行并疏散邪气的药。
只是邪气浅薄的，忌讳峻猛通利的药物；正气虚弱的，忌讳雄悍刚烈的药物；热象多的，忌讳温燥的药物；寒象多的，忌讳清凉的药物。凡是出现热盛口渴、烦躁不安的，喜欢用干葛，但呕吐恶心的则忌用；凡是寒热往来的，适宜用柴胡，但泄泻的则忌用；寒邪在上部的，适宜用升麻、川芎，但体内热气炎上者则忌用。这些药性的适用与禁忌，是应当辨别的。至于配合用药的方法，更应当掌握要点，凡是平和药兼用清凉药，自然形成凉散的效果；平和药兼用暖性药，也可以温通经络；需要大温的，用热性药辅助热性药；需要大凉的，用寒性药辅助寒性药。这其中的运用权变，毫厘之间的进退，自有伸缩变化的奥妙，又何必拘泥固执，以限制无穷变化的病变呢！这没有别的原因，就在于不知道张仲景的本意罢了。
1. The use of "San" (dispersing agents) is to disperse exterior syndromes. Observing Zhang Zhongjing, for Taiyang disease (diseases caused by pathogenic factors affecting the Taiyang meridian), he used Mahuang Tang (Ephedra Decoction); for Yangming disease (diseases caused by pathogenic factors affecting the Yangming meridian), he used Shengma Gegen Tang (Cimicifugae and Puerariae Decoction); for Shaoyang disease (diseases caused by pathogenic factors affecting the Shaoyang meridian), he used Xiaochaihu Tang (Minor Bupleurum Decoction). These serve as the standards for dispersing exterior pathogens. Later generations followed this principle but failed to apply it flexibly, due to a lack of understanding of its true intent.
The nature of Mahuang (Ephedrae Herba) is potent, penetrating, and vigorous. In cases where Yin-cold pathogens reside in the exterior of the Taiyang meridian, if the cold toxin has penetrated deeply, only such a potent agent can reach and dispel it. Therefore, this formula was formulated not because Taiyang diseases must exclusively use Mahuang, but rather to address specific conditions. If Mahuang were used to treat Yangming or Shaoyang syndromes, the cold would still be dispersed; however, one must fear that its excessive strength might inadvertently damage Qi. Does this imply that specific herbs are absolutely immutable for specific meridians? No, it merely involves distinguishing the degree of severity. Thus, Shengma (Cimicifugae Rhizoma) and Gegen (Puerariae Radix) used for Yangming disease naturally extend their action to the Taiyang and Shaoyang meridians. Similarly, Chaihu (Bupleuri Radix) used for Shaoyang disease naturally enters the Taiyang and Yangming meridians.
However, when employing dispersing methods, one must understand the urgency or mildness of the herb's nature and distinguish between the flavors and thermal properties (cold/warm). When applied appropriately, treatment across all meridians can yield excellent results. For instance:
- Mahuang (Ephedrae Herba) and Guizhi (Cinnamomi Ramulus) are potent dispersing agents;
- Fangfeng (Saposhnikoviae Radix), Jingjie (Perillae Folium), and Zisu (Perillae Fructus) are mild dispersing agents;
- Xixin (Asari Radix et Rhizoma), Baizhi (Angelicae Dahuricae Radix), and Shengjiang (Zingiberis Rhizoma Recens) are warm dispersing agents;
- Chaihu (Bupleuri Radix), Gegen (Puerariae Radix), and Bohe (Menthae Haplocalycis Herba) are cool dispersing agents;
- Qianghuo (Notopterygii Rhizoma et Radix) and Cangzhu (Atractylodis Rhizoma) disperse pathogens while traversing meridians and removing dampness;
- Shengma (Cimicifugae Rhizoma) and Chuanxiong (Ligustici Chuanxiong Rhizoma) lift sunken Qi upward and disperse pathogens.
Specific contraindications apply:
- For superficial pathogens, avoid potent and penetrating agents;
- For deficient Qi, avoid aggressive and harsh agents;
- For excess heat, avoid warm and drying agents;
- For excess cold, avoid cool and clearing agents.
Regarding specific clinical presentations:
- Patients with heat-induced thirst and restlessness benefit from Gegen (Puerariae Radix), but those with vomiting and nausea should avoid it;
- Patients with alternating chills and fever suit Chaihu (Bupleuri Radix), but those with diarrhea should avoid it;
- Cold pathogens located in the upper jiao suit Shengma (Cimicifugae Rhizoma) and Chuanxiong (Ligustici Chuanxiong Rhizoma), but those with internal heat flaring upward should avoid them.
These indications and contraindications regarding herbal properties must be clearly distinguished. Regarding combination strategies, key principles must be grasped: combining mild agents with cooling agents creates a cooling-dispersing effect; combining mild agents with warming agents can warm the meridians; for strong warming needs, hot-natured herbs support other hot-natured herbs; for strong cooling needs, cold-natured herbs support other cold-natured herbs. The flexibility in application allows for subtle adjustments, possessing the wonder of adaptation. Why then adhere rigidly to fixed rules, thereby limiting the response to infinite variations in pathological changes? This issue stems simply from a failure to understand Zhang Zhongjing’s original intent.