（附翻胃）
呕者有物在中。其所来之道远。故必呕而出也。吐者亦有物在中。其所来之道近。故一
吐而即出也。分而言之。微有不同。合而言之。同归于火。饮食痰涎停积不化。胃气一升。则涌
而出矣。其与翻胃相似。而实各有所属翻胃属寒。呕吐属热。惟其热也。故其出也。无定时
。或随食随吐。或食良久而后吐。随食随吐者。火邪急速不及入胃而即出。无呕吐之苦。无
挥咯之劳是即吐之谓也。食良久而后吐者。火犹稍缓。必入胃余时。委曲而出。酸苦万状。
伤神劳精。肠卷而腹急。是即呕之谓也。而所出之物。亦不甚尽惟翻也。则阴气下结。水谷
暂容。朝食则暮吐。暮食则朝吐。或朝食至午而吐。午时至暮而吐。其吐必尽所食日日如此
不少愆期。盖胃家受寒不能运化。自不容于不出。此翻胃与呕吐所以不同也。又有吞酸吐酸
者何也。盖饮食入胃。胃弱不能消。而又挟肝火。是以作酸。浮饮停蓄。变为酸痰。肝火升
即吐。肝火降即吞。其吞与吐。皆肝火升降之所为也。故治呕吐者。必治其热。治翻胃者。
必治其寒。治吞酸吐酸。必抑其肝。而后所投之药无不中矣。
(Attached: Fanwei / Regurgitation)
Ou (vomiting with sound and effort) refers to the presence of solid matter in the stomach. The path from which it comes is distant; therefore, it must be vomited out. Tu (vomiting without sound or great effort) also refers to the presence of matter in the stomach. However, the path from which it comes is near; thus, it is expelled immediately upon vomiting. Analyzed separately, there are slight differences; considered together, both are attributed to Fire pathogen. When food and phlegm-fluids stagnate and accumulate without being digested, Stomach Qi rebels upward, causing them to surge out. This resembles Fanwei (regurgitation), yet they have distinct etiologies: Fanwei belongs to Cold, while Ou/Tu belongs to Heat. Due to this Heat, the timing of expulsion is irregular. Some vomit immediately after eating; others vomit long after eating. Those who vomit immediately after eating do so because the Fire pathogen is rapid and urgent, preventing the food from entering the Stomach before being expelled. There is no suffering associated with retching, nor the labor of dry heaving; this is defined as Tu. Those who vomit long after eating do so because the Fire is slightly slower; the food must enter the Stomach and remain for some time before being expelled gradually. The taste is extremely sour and bitter, damaging the Shen (Spirit) and exhausting Jing (Essence), leading to contracted intestines and abdominal urgency; this is defined as Ou. Furthermore, the expelled matter is not always completely empty. In contrast, Fanwei involves Yin Qi binding downward, temporarily holding water and grain. Food eaten in the morning is vomited in the evening, and food eaten in the evening is vomited in the morning, or food eaten in the morning is vomited at noon, and food eaten at noon is vomited in the evening. The vomiting always expels all ingested food, occurring daily without fail. This is because the Stomach has suffered Cold and cannot transform and transport, making retention impossible and necessitating expulsion. This is why Fanwei differs from Ou/Tu.
What about Swallowing Acid (Tun Suan) and Vomiting Acid (Tu Suan)? Generally, when food enters the Stomach, weak Stomach Qi fails to digest it, compounded by Liver Fire, resulting in acidity. Floating fluids stagnate and transform into acidic phlegm. When Liver Fire ascends, acid is vomited; when Liver Fire descends, acid is swallowed. Both swallowing and vomiting are caused by the ascending and descending movements of Liver Fire. Therefore, treating Ou/Tu requires addressing the Heat; treating Fanwei requires addressing the Cold; and treating Swallowing/Vomiting Acid requires suppressing the Liver. Only then will the administered medicines hit the mark accurately.
A pulse at the Guan position that is slippery but uneven in magnitude indicates inevitable rebellious vomiting. It is also said that vomiting arises from no other cause than a Cun (inch) position pulse that is tight, slippery, and rapid; a slightly rapid pulse suggests mild Blood deficiency. A pulse that is floating alone with a Kou (cork-like) quality indicates blood stasis. The most contraindicated pulse qualities are choppy and weak.