阳数奇，阴数偶，善用药者，性理有畏恶，气味有薄浓，须其相当，然后合而服之，气
之高下，病之远近，证之中外，势之缓急，随宜致用，则所施无不当矣，古人有奇偶之制，
君臣赞助之意也。又有小大之殊，或单行，或复用，数止一二者，其制小，一三五而成者，
其制中，一三九而后备者，其制大，小则数多而气味浓，大则数少而气味薄，以奇治近，以
偶治远，顺阴阳也。汗者不以奇，下者不以偶，和阴阳也，补上治上制以缓，补下治下制以
急，治之常也，近而奇偶，必小其服，远而奇偶，必大其服，所以从权也。用奇偶而至于从
权，则方制本奇，而轻重之数偶者，尤其所宜。故曰奇之不去则偶之，偶之不去则反佐以取
之，所谓寒热温凉，从其病也。
治法有以五毒攻其病者，其用毒之约，大毒治病，十去其六，常毒治病，十去其七，小
毒治病，十去其八，无毒治病，十去其九，是则有毒虽善，曾不若无毒之为全也。或不得已
而用毒攻毒者，亦在权其轻重而已，故曰因其轻而扬之，因其重而减之，可汗可下，不可妄
施；可越可引，不可倒置。制有奇偶，虽在审其远近，然奇之不去则偶之，偶之不去则反佐
以取之，犹不可执一也。性有温凉，虽在适其寒热，然治寒以热，必凉而行之。治热以寒，
必温而行之，又欲其调和也，以至服有小大，用有多寡，随宜制权，以适事为故，惟通变者
能之。
阳数为奇数，阴数为偶数。善于用药的人，必须了解药物性味之间的相畏与相恶关系，以及气味的厚薄浓淡，使它们相互匹配，然后配合服用。根据气机的升降、病位的远近、证候的内外部、病势的缓急，灵活适宜地运用，那么所施用的治法就没有不恰当的。古人制定了奇方和偶方的制度，这是体现君臣佐使辅助配合的意思。又有小方、中方、大方之别：药味数量只有一或两味的，属于小方；由一、三、五味组成的，属于中方；由一、三、九味组成并备齐的，属于大方。小方虽然药味多但气味浓厚（注：此处原文逻辑似有争议，通常小方药少力专，但依原文翻译），大方虽然药味少但气味淡薄。用奇方治疗近处的病，用偶方治疗远处的病，这是顺应阴阳的道理。发汗法不用奇方，攻下法不用偶方，这是为了调和阴阳。补益上部或治疗上部的病，制方宜缓；补益下部或治疗下部的病，制方宜急，这是治疗的常规。病位近而使用奇方或偶方，服药量必须小；病位远而使用奇方或偶方，服药量必须大，这是权宜之计。使用奇偶之法以至于权宜变通，那么方剂本属奇数，而轻重数量的偶数，更是适宜的。所以说，用奇方无效则改用偶方，用偶方无效则采用反佐法以取效，所谓寒热温凉，是顺从病情的需要。
治疗方法中有用“五毒”来攻治病邪的，使用毒药要谨慎。大毒药物治疗疾病，病去六分即止；常毒药物治疗疾病，病去七分即止；小毒药物治疗疾病，病去八分即止；无毒药物治疗疾病，病去九分即止。由此可见，有毒的药物虽然有效，但不如无毒的药物能保全正气。如果不得已而用毒药攻毒，也在于权衡其轻重程度罢了。所以说，因病情轻扬而用发散法，因病情沉重而用削减法，可汗可下，不可妄加施用；可涌吐可引导，不可颠倒错置。方剂有奇偶之分，虽然在于审察病位的远近，但如果奇方无效则改用偶方，偶方无效则用反佐法取效，仍然不能固执一端。药性有温凉之分，虽然在于适应寒热的病情，但是治疗寒证用热药，必须辅以凉药引导；治疗热证用寒药，必须辅以温药引导，这是为了调和药性。至于服药量的大小，用量的多少，都要随宜权变，以适合事情的需要为准则，只有通晓变化的人才能做到。
Yang numbers are odd, and Yin numbers are even. Those skilled in using herbs must understand the mutual fear and aversion (mutual inhibition or antagonism) of herbal properties, as well as the thickness and density of their qi and flavor, ensuring they correspond to each other before combining them for administration. Depending on the ascending and descending of qi, the proximity or distance of the disease, the interior or exterior nature of the syndrome, and the urgency or slowness of the pathological trend, one should apply treatments flexibly and appropriately; thus, no application will be inappropriate. The ancients established the system of Odd formulas (formulas with an odd number of ingredients) and Even formulas (formulas with an even number of ingredients), reflecting the principle of mutual assistance among Sovereign, Minister, Assistant, and Envoy herbs. There are also distinctions between Small, Medium, and Large prescriptions: those with only one or two ingredients are Small prescriptions; those composed of one, three, or five ingredients are Medium prescriptions; and those composed of one, three, nine, etc., ingredients are Large prescriptions. Small prescriptions have more ingredients but stronger flavors (Note: This interpretation follows the literal text provided, though traditional theory often varies); Large prescriptions have fewer ingredients but weaker flavors. Using Odd formulas to treat diseases located near the surface, and Even formulas to treat diseases located far away, conforms to the principles of Yin and Yang. Sweating methods do not use Odd formulas, and purgative methods do not use Even formulas, which serves to harmonize Yin and Yang. Tonifying the upper or treating diseases in the upper body requires a slow-acting prescription; tonifying the lower or treating diseases in the lower body requires a fast-acting prescription; this is the standard method of treatment. When the disease is near and Odd or Even formulas are used, the dosage must be small; when the disease is distant and Odd or Even formulas are used, the dosage must be large; this is an adaptation to circumstances. When applying Odd and Even methods to the point of adapting to circumstances, if the formula base is Odd, then the Evenness in weight and quantity is particularly suitable. Therefore, it is said: "If the Odd formula fails, use the Even formula; if the Even formula fails, use counter-assistance (fan zuo) to obtain the effect." This refers to Cold, Heat, Warmth, and Coolness, following the needs of the disease.
In therapeutic methods, there are those that use "Five Poisons" to attack the disease. The use of poisonous substances requires caution. When treating a disease with Great Poison herbs, stop when six-tenths of the disease is eliminated; when treating with Common Poison herbs, stop when seven-tenths is eliminated; when treating with Small Poison herbs, stop when eight-tenths is eliminated; and when treating with Non-poisonous herbs, stop when nine-tenths is eliminated. Thus, although toxic herbs are effective, they are not as complete in preserving health as non-toxic herbs. If one is forced to use toxic herbs to attack toxicity, one must weigh their severity. Therefore, it is said: "Because the condition is light and floating, disperse it; because the condition is heavy and sinking, reduce it." Sweating or purging may be used, but not arbitrarily; emesis or guiding may be used, but not inverted. Prescriptions have Odd and Even distinctions, which depend on assessing the proximity or distance of the disease. However, if the Odd formula fails, switch to the Even formula; if the Even formula fails, use counter-assistance to obtain the effect; one must not adhere rigidly to one approach. Herbal properties vary in Warmth and Coolness, which must suit the Cold or Heat of the condition. However, when treating Cold with Hot herbs, one must administer them with Cool herbs as guidance; when treating Heat with Cold herbs, one must administer them with Warm herbs as guidance; this is to harmonize the treatment. Regarding the size of doses and the amount of usage, one must adapt to circumstances and adjust accordingly, taking suitability for the matter as the goal. Only those who understand change can achieve this.