Which TCM herbs help with abdominal bloating?

In TCM, abdominal bloating (腹胀) is typically attributed to Qi stagnation, dampness accumulation, or food stagnation in the middle burner (Spleen-Stomach system). Several herbs are traditionally used to address bloating by promoting Qi movement and transforming dampness: Chen Pi (aged tangerine peel, Citri Reticulatae Pericarpium) regulates Spleen-Stomach Qi and dries dampness; Mu Xiang (Aucklandiae Radix) moves Qi and relieves pain, particularly for intestinal bloating; Sha Ren (Amomi Fructus) transforms dampness and moves Qi, especially for bloating with reduced appetite; and Fu Ling (Poria) drains dampness and supports the Spleen. These herbs appear in classic formulas such as Xiang Sha Liu Jun Zi Tang (for Spleen deficiency with Qi stagnation) and Ping Wei San (for dampness in the middle burner). The choice of herb depends on the underlying pattern: bloating after eating with fatigue suggests Spleen deficiency; bloating worsened by stress suggests Liver Qi stagnation; bloating with heavy sensation and loose stools suggests dampness.

Pharmacological research on individual TCM herbs for bloating has identified several relevant properties. Chen Pi contains hesperidin and nobiletin, which have shown carminative and anti-inflammatory effects in vitro and in animal models. Mu Xiang (Saussurea) contains costunolide and dehydrocostus lactone, which may promote gastrointestinal motility. Sha Ren (Amomum) essential oil has demonstrated spasmolytic effects on intestinal smooth muscle. However, clinical trials specifically evaluating these herbs for bloating as a primary outcome are limited. The current TCMIO reference set did not identify robust RCTs of single-herb interventions for bloating. Most clinical evidence comes from formula-level studies for conditions such as functional dyspepsia and IBS, where bloating is a secondary outcome.