胃为水谷之海。资生之本也。故曰有胃气则生。无胃气则死。胃脉六部皆有。盖六部皆有浮中沉。中即胃脉也。此
处分别甚难。即于足阳明候之。使其脉中和。无过不及。急疾则为无胃气。丹溪更有候胃气法。谓男子以气成胎。则气
为之主。女子挟血成胎。则血为之主。男人久病。右脉克于左者。有胃气也。病虽重可治。女人久病。左脉克于右者。
有胃气也。病虽重可治。反此者虚之甚也。更有趺阳。亦胃气脉。在足跗上五寸骨间。动脉波阳者。是病重。切其旺衰。
以决死生。
看脉先辨虚实。滑利力薄无神则为虚。涩滞力浓有神则为实。实则损之。一定之法。又必损其子。若母令有余之势
易杀。虚者益之。必然之理。又必益其子。若母令不足之势易培。子母亦有虚实。如某脉病。母脉虚。急补母。庶本脉
可得母养。亦必兼补本脉之子。令彼无所泄。某脉病。子脉虚。争补子。庶本脉不为子累。又宜兼补本脉之母。令彼有
所资。
又贼脉不宜盛。贼盛必乘邪淫来胜本脉。法当培本脉。伐贼脉又急益贼之鬼令其制贼。损贼之母。俾其无靠。贼之母。
即本脉之妻也。此皆生克之理之最微者。不识此。不能治病。
经云。上部有脉。下部无脉。其人当吐不吐则死。观当吐二字便知胸中有物。填塞至阴。抑遏肝气。而绝升生之化
也。故吐之则愈。不吐则暴死。若使其人胸中无物可吐。此阴绝于下也。非死症而何。经又云。下部有脉。上部无脉。
虽困无能为害。此虽至理。亦不可执。上不至关为阳绝。况无脉乎。明者可以悟矣。若覆病患之手而脉出者。此运气不
应之脉。非无脉也。论在运气脉中。
胃是水谷汇聚的海洋，也是人体生命活动的根本。所以说，脉中有胃气就能生存，没有胃气就会死亡。胃脉在寸关尺六部中都有体现，因为每一部脉都有浮、中、沉三种取法，其中“中”取法即对应胃脉。这一点区分起来非常困难，因此通常在足阳明胃经的趺阳穴处进行候诊。如果脉象平和，不偏盛也不偏衰，就是正常的；如果脉象急疾躁动，就是没有胃气的表现。朱丹溪还有另一种候察胃气的方法，他认为男子以气为主形成胎元，所以气是主导；女子以血为主形成胎元，所以血是主导。男子久病时，如果右脉（气分）克制左脉（血分），说明有胃气，即使病情严重也可以治疗。女子久病时，如果左脉（血分）克制右脉（气分），说明有胃气，即使病情严重也可以治疗。反之，则属于极度虚弱的情况。此外，趺阳脉也是反映胃气的脉象，位于足背上方五寸两骨之间的动脉处。通过切按其旺盛或衰弱，可以判断生死预后。
诊脉首先要辨别虚实。脉象滑利但力量薄弱、缺乏神气的是虚证；脉象涩滞但力量充实、有神气的是实证。对于实证，应当采用泻法，这是确定的法则。又必须同时泻其子脏（根据五行相生关系，实则泻其子）。如果母脏导致邪气有余而亢盛，容易伤害本脏。对于虚证，应当采用补法，这是必然的道理。又必须同时补其子脏。如果母脏导致正气不足而虚弱，容易培补本脏。子与母之间也有虚实的变化。例如某经脉生病，如果母脉虚弱，应当紧急补益母脉，这样本脉才能得到母脉的滋养；同时也必须兼补本脉的子脉，使本脉的气血不再被过度泄耗。如果某经脉生病，子脉虚弱，应当紧急补益子脉，这样本脉就不会被子脉拖累；同时也应该兼补本脉的母脉，使本脉有所资助。
另外，贼脉（相克之脉）不宜过盛。如果贼脉过盛，必定会乘虚侵袭并战胜本脉。治疗方法应当培补本脉，攻伐贼脉；同时要紧急补益克制贼脉的“鬼”（即贼脉的所不胜，如金克木，木为贼，金为鬼），使其制约贼脉；还要损伤贼脉的母脏，使其失去依靠。贼脉的母脏，实际上就是本脉的配偶（妻）脏。这些都是生克理论中最精微的部分。如果不理解这些原理，就不能治病。
《内经》说：上部有脉，下部无脉，病人应当呕吐却不呕吐，就会死亡。从“当吐”这两个字就可以知道，胸中有实物阻塞，填塞至阴部位，抑制遏止了肝气的升发生机。所以用催吐法治疗就会痊愈，不催吐就会突然死亡。如果病人胸中没有可吐之物，这就是阴气在下部断绝了。这难道不是死症吗？《内经》又说：下部有脉，上部无脉，虽然困顿但不会造成危害。这虽然是至理名言，但也不可固执拘泥。如果脉象上不到关部，称为阳绝，何况是完全无脉呢？高明的人可以从这里领悟。如果把病人的手翻转过来，脉象反而出现，这是运气不应时的脉象，并不是真正的无脉。这在运气脉法的论述中有详细说明。
The Stomach is the sea of water and grain, the root of nourishment. Therefore, it is said that if there is Stomach Qi (Wei Qi), there is life; if there is no Stomach Qi, there is death. The Stomach pulse can be felt in all six positions (Cun, Guan, Chi on both wrists). This is because each position has Floating (Fu), Middle (Zhong), and Deep (Chen) levels; the Middle level corresponds to the Stomach pulse. Distinguishing this is very difficult, so one should inspect it at the Foot-Yangming (Zu Yangming) channel, specifically the Doucheng point (Doucheng acupoint). If the pulse is moderate, neither excessive nor deficient, it is normal. If the pulse is rapid and urgent, it indicates a lack of Stomach Qi. Danxi [Zhu Zhenheng] had another method for inspecting Stomach Qi. He stated that men form their constitution primarily through Qi, so Qi is dominant; women form their constitution primarily through Blood, so Blood is dominant. In men with chronic illness, if the Right pulse (Qi aspect) overcomes the Left pulse (Blood aspect), it indicates the presence of Stomach Qi, and even severe illness is treatable. In women with chronic illness, if the Left pulse overcomes the Right pulse, it indicates the presence of Stomach Qi, and even severe illness is treatable. The reverse indicates extreme deficiency. Additionally, the Doucheng pulse (Fuyang pulse) also reflects Stomach Qi. It is located in the interosseous space five cun above the foot dorsum, at the arterial beat of Yangming. By palpating its vigor or weakness, one can determine life and death.
When examining the pulse, one must first distinguish between Deficiency (Xu) and Excess (Shi). A slippery pulse with weak force and lacking Shen (Spirit/Essence) indicates Deficiency. A choppy/stagnant pulse with strong force and possessing Shen indicates Excess. For Excess conditions, one must reduce/drain them; this is a fixed principle. Furthermore, one must drain the "Child" organ (according to the Five Elements generation cycle). If the Mother organ causes an excess pattern, it may easily harm the affected organ. For Deficiency conditions, one must tonify/supplement them; this is a necessary logic. Furthermore, one must tonify the "Child" organ. If the Mother organ causes a deficiency pattern, it facilitates the nurturing of the affected organ. There are also Deficiency and Excess dynamics between Mother and Child. For example, if a specific meridian is diseased and the Mother pulse is deficient, urgently tonify the Mother so that the primary meridian can receive nourishment from it; simultaneously, one must tonify the Child of the primary meridian to prevent excessive leakage from the primary meridian. If a specific meridian is diseased and the Child pulse is deficient, urgently tonify the Child so that the primary meridian is not burdened by it; additionally, one should tonify the Mother of the primary meridian to provide support.
Furthermore, the "Thief" pulse (the controlling/overcoming pulse) should not be vigorous. If the Thief pulse is too strong, it will inevitably invade and overcome the primary pulse. The treatment method should be to tonify the primary pulse and attack the Thief pulse. Simultaneously, urgently tonify the "Ghost" (the element that controls the Thief, e.g., Metal controls Wood, so Metal is the Ghost of Wood) to restrain the Thief; and damage the Mother of the Thief so it loses its support. The Mother of the Thief is essentially the Wife organ of the primary pulse. These are the most subtle aspects of the generating and controlling cycles. Without understanding this, one cannot cure diseases.
The Classics state: "If there is a pulse in the upper part but none in the lower part, the patient should vomit; if they do not vomit, they will die." From the phrase "should vomit," one can infer that there is a physical obstruction in the chest, blocking the Lower Yin, suppressing Liver Qi, and cutting off the transformative process of rising and generating life. Therefore, inducing vomiting will lead to recovery; without vomiting, sudden death occurs. If the patient has nothing in the chest to vomit, this indicates the severance of Yin in the lower part. Is this not a fatal condition? The Classics also state: "If there is a pulse in the lower part but none in the upper part, although the patient is distressed, it will not cause harm." Although this is a profound truth, it should not be applied rigidly. If the pulse does not reach the Guan position, it is called Yang Severance (Yang Jue); how much more so if there is no pulse at all? Wise individuals can comprehend this. If the patient's hand is turned over and the pulse appears, this is a pulse inconsistent with the prevailing Qi transformation (Yunqi); it is not true absence of pulse. This is discussed in detail in the section on Pulse Patterns of Qi Transformation.