Herbs that relieve food stagnation are able to promote digestion and dissolve food accumulation. Although food stagnation is not commonly seen nowadays in the developed countries because of the influence of healthy dietary principles, it may still happen in certain situations. First of all, in infants, since the Spleen and Stomach are not fully developed and the parents may lack experience or knowledge of the best diet for children, the child may suffer from indigestion. Secondly, in people with a weak constitution or who suffer from chronic disease, because the functions of the Spleen and Stomach are insufficient, food may tend to stagnate in the Middle Jiao. Thirdly, in elderly people, since the digestion slows with age, indigestion may easily happen. Acute or Excess cases of food stagnation may also occur when on holiday if the diet is changed significantly or the person overindulges.

Food stagnation is caused by the obstruction of the Qi in the Middle Jiao. The main symptoms are fullness in the stomach, belching, nausea, vomiting with a foul smell, distending pain in the abdomen and constipation or diarrhea. The tongue body is normal or slightly red and the coating is thick, white or slightly yellow. The pulse is slippery, forceful and rapid. In chronic cases of food stagnation, especially in those people with Spleen and Stomach deficiency, symptoms of Qi and Blood deficiency may appear. In children, it may affect their general health and development.

Herbs that relieve food stagnation should be used with caution because they can digest, dissolve and transport food; therefore they may injure the Stomach, Spleen, Qi and Blood too. They are generally used for only a short treatment course. When the accumulated food has been digested, these herbs should be stopped. In people who suffer from indigestion with deficiency of the Spleen and Stomach, these herbs should be used together with herbs that tonify the Spleen and Stomach. In addition, these herbs are normally not used in large dosages, and are often used together with other herbs to enhance the effect, such as herbs that promote the Qi movement, eliminate Dampness or clear Heat in the Middle Jiao. For patients who have a weakness of the Spleen and Stomach, herbs that are slightly warm in temperature are often used to warm the Middle Jiao and accelerate the function of these organs.

These three herbs have the function of promoting digestion. Since they are often used together and are very effective for treating food stagnation, they are given a particular name: Jiao San Xian. In Chinese, ‘ Jiao’ means ‘deep-dry-fried’, ‘S an’ means ‘three’ and ‘ Xian’ means ‘immortal’. In other words, the name means ‘three very effective herbs’. These herbs are often deeply dry-fried until their colors have changed to deep brown. It is believed that they are then more easily digested and work particularly on the Middle Jiao.

These three herbs are often used together because they have different functions and can enhance each other’s therapeutic effects. Mai Ya is sweet and neutral, and enters the Spleen and Stomach meridians; it especially aids the digestion of wheat, rice and fruits. Shen Qu is pungent, sweet and warm, and enters the Spleen and Stomach meridians; it particularly aids the digestion of cereals and dispels the effects of alcohol. Shan Zha is sour, sweet and slightly warm, and enters the Spleen, Stomach and Liver meridians; it especially aids the digestion of meat, fat and milk. Because in most cases of food stagnation these foods and drinks are all involved, the three herbs are often used together.

These three herbs are all used for stagnation of wheat, rice and fruits, but their strengths are different. Lai Fu Zi is the strongest; it is pungent, sweet and neutral, and enters the Lung and Spleen meridians. It can direct the Lung-Qi to descend, soothe the Stomach-Qi and promote the bowel movement. It can also eliminate Phlegm whether in the Lung or in the Stomach. Lai Fu Zi is especially suitable for use when the food stagnation causes nausea, vomiting and constipation and the tongue has a thick, sticky and white coating.

Mai Ya is gentler than Lai Fu Zi and it can dissolve stagnation of wheat, rice and fruits. But, unlike Lai Fu Zi, it has no function in promoting the Qi movement.

Gu Ya is the weakest herb of the three. It is gentle and slow in action, but its strong point is that it can tonify the Spleen and Stomach, so it can be used for a longer period of time than the others. Gu Ya can also aid the digestion of cereals, so can be used for all starchy foods. It is particularly suitable for people who suffer from indigestion in Deficiency conditions.