Changji'an Capsule

To preliminarily evaluate the efficacy and safety of Changji'an Capsule in patients with diarrhea-predominant irritable bowel syndrome (liver qi invading spleen syndrome).

(1) To preliminarily evaluate the effectiveness of Changji'an Capsules in treating irritable bowel syndrome (diarrhea type) (liver depression and spleen deficiency syndrome) compared with placebo; (2) To preliminarily evaluate the safety of Changji'an Capsules in treating irritable bowel syndrome (diarrhea type) (liver depression and spleen deficiency syndrome); (3) To explore the optimal dose of Changji'an Capsules in treating irritable bowel syndrome (diarrhea type) (liver depression and spleen deficiency syndrome).