Diarrhea is the frequent passage of loose or watery stools. In Chinese medicine, diarrhea is often associated with the presence of dampness, which may affect the Spleen either as the source of the dampness or as the target of external dampness. Diarrhea can be divided into two main categories: excess and deficiency. Excess patterns are typically associated with a pathogenic influence in the yang ming and tai yin levels that the body tries to eliminate through diarrhea. Accumulation of dampness, along with interference from qi, blood, or food stasis, can disrupt the digestive process and obstruct the flow of qi. This type of diarrhea may be acute, urgent, and frequent, or it may develop slowly and become chronic and persistent. Deficient patterns, on the other hand, are primarily associated with weakness in the Spleen. A weak Spleen produces dampness as a result of its inefficiency, and this dampness sinks into the lower burner and causes diarrhea. Once the Spleen is weak, it is more vulnerable to invasion by external pathogens.