Yangwei Zengye Decoction for Anorexia and Dry Mouth
Yangwei Zengye Decoction ("Stomach-Nourishing and Fluid-Engendering Decoction") is an empirical formula in contemporary TCM pediatrics. Its composition is: shihu (Dendrobium stem) 12g, wumei (Smoked Mume fruit) 12g, baishao (White Peony root) 12g, beishashen (Glehnia root) 15g, yuzhu (Polygonatum odoratum rhizome) 10g, gancao (Licorice root) 5g. This is a water-decocted formula; one dose daily, taken morning and evening. For severe cases, two doses daily may be taken, divided into four portions.
This formula is used to treat symptoms caused by insufficient stomach yin: dry mouth with excessive drinking, anorexia, dry skin, dry and hard stools, peeled or mirror-like tongue coating (or a red tongue with scant moisture), and a fine pulse. These symptoms are commonly seen in pediatric anorexia, Sjogren's syndrome, gastritis, gastric cancer, sequelae of radiotherapy, sequelae caused by analgesics, Behcet's disease, and TCM patterns of yin injury from febrile disease. Therefore, this formula can be used for the above diseases presenting with the pattern of stomach yin deficiency. Modern pharmacological studies show that this formula promotes gastric juice secretion and assists digestion, and can also enhance human immunity.
In this formula, shihu, baishao, beishashen, and yuzhu all belong to the TCM category of yin-nourishing herbs. Gancao also has the effects of fortifying the spleen and generating fluids. Wumei has the effects of astringing the lung, securing the intestines, stopping cough, and generating fluids. In summer, some catering businesses often offer wumei tang (smoked plum drink) to diners; it both quenches thirst and generates fluids while improving appetite. According to traditional TCM theory, these herbs combined have the effect of supplementing yin and generating fluids, making them suitable for patients with yin-fluid deficiency.
Although this formula can also relieve constipation, its laxative effect is weak. If the patient's constipation is relatively severe, this formula can be combined with Zengye Decoction (Fluid-Engendering Decoction), adding xuanshen (Scrophularia root) 15–30g, maidong (Ophiopogon tuber) 12–24g, and shengdi (Rehmannia root) 12–24g. If constipation is still not fully relieved after combining with Zengye Decoction, huomaren (Cannabis fruit) 30–60g and roucongrong (Cistanche) 30–60g may be added. For patients with stomach yin deficiency and constipation caused by chronic disease or analgesic use, harsh laxatives such as mangxiao (Mirabilite) and dahuang (Rhubarb) should not be used directly; gently treating with this formula is more appropriate.
If stomach heat is prominent with dry mouth and bitter taste, pugongying (Dandelion), huangqin (Scutellaria root), zhizi (Gardenia fruit), and yinchen (Artemisia capillaries) may be added to Yangwei Zengye Decoction to clear the stomach and drain heat. Generally, such patients have hepatobiliary disease in modern medicine; severe cases may present with elevated bilirubin and abnormal liver function. While using this formula to relieve symptoms, some liver-protecting and gallbladder-promoting herbs can also be used.
For dry mouth and tongue caused by Sjogren's syndrome or post-radiotherapy cancer, lugen (Rhizoma Phragmitis) and shenshen (Morus fruit) may be added when using this formula to enhance its efficacy. If stomach yin deficiency is accompanied by kidney yin deficiency with sore and weak lower back and knees, shudihuang (Prepared Rehmannia), shanzhuyu (Cornus fruit), mohanlian (Eclipta), and nvzhenzi (Ligustrum fruit) may be added to supplement kidney yin.
In severe anorexia, besides the above symptoms, there may also be abdominal fullness and distension, pain in the chest and hypochondria, belching and acid regurgitation, five-center heat, and even excessive sweating. For such patients, stomach-strengthening and digestion-promoting herbs such as jineijin, jiaoshanzha (charred hawthorn), jiaomaiya (charred barley malt), and jiaoshenqu (charred medicated leaven) may be appropriately added, along with qi-moving and digestion-promoting herbs such as wuyao (Lindera root), xiangfu (Cyperus rhizome), and laifuzi (Radish seed).
If the patient also has severe insomnia, this formula may be combined with Gan Mai Dazao Decoction (Licorice, Wheat, and Jujube Decoction), adding huaxiaomai (Huai wheat) 30g and dazao (Jujube) 5–7 pieces.