Chronic diarrhea belongs to the category of “prolonged diarrhea” in traditional Chinese medicine, and the addition of Huo Park Xia Ling Tang can be used to treat prolonged diarrhea with weak spleen and stomach and internal dampness, but it is not suitable for prolonged diarrhea with weak kidney yang, and liver qi multiplying the spleen (liver qi excessively encroaching on the spleen). Weakness of the spleen and stomach type of prolonged diarrhea is due to the deficiency of the spleen and stomach, resulting in the spleen’s function of transporting and transforming water and dampness is out of order, water and dampness are generated internally, and the intestinal tract’s function of clearing and urinating turbidity is out of order, and then diarrhea occurs, and the treatment mainly focuses on strengthening the spleen and benefiting the qi, and transforming dampness to stop diarrhea. The main function of Huo Park Xia Ling Tang is to regulate qi, dissolve dampness, and harmonize the middle, so the use of Huo Park Xia Ling Tang plus subtractions can be used to treat prolonged diarrhea of the weak spleen and stomach type. However, chronic diarrhea can also be caused by kidney yang deficiency and liver qi multiplying the spleen, so the treatment mainly focuses on warming the kidney and strengthening the spleen, fixing the astringency to stop diarrhea, and suppressing the liver to support the spleen, so it is not possible to use Huopu Xia Ling Tang Plus Extension to treat chronic diarrhea caused by kidney yang deficiency and liver qi multiplying the spleen. It is recommended that people with chronic diarrhea consult a professional doctor in time to avoid delays.