Effectiveness of the Chinese herbal formula TongXieYaoFang for irritable bowel syndrome: A systematic review

Objective: Irritable bowel syndrome (IBS) is a common problem, but treatment is unsatisfactory. Although Chinese herbal medicines have been tried, there are limited data to support their usage. The authors set out to systematically review the effectiveness of the Chinese herbal medicine TongXieYaoFang (TXYF) and TXYF with different Chinese herbal additions (TXYF-A) in the management of IBS in order to make evidence-based recommendations. Methods: The authors searched the literature to identify randomized trials of TXYF or TXYF-A for patients with IBS by using MEDLINE,® EMBASE, the Cochrane Controlled Trials Register (CCTR), the Cochrane Complementary Medicine Fields Specialized Register from 1966 to 2004, the CMB Disc database from January 1978 to December 1988, and the Full Text Chinese Journal database from January 1994 to December 2004. Standard forms regarding study design, treatment course, outcome measures, and adverse events were used to abstract data. Studies were assigned a quality score based on published methodology. Relative risk (RR) and 95% confidence interval (CI) were analyzed. Results: Twelve studies (n = 1125) that met the criteria for review were identified. There was heterogeneity in the studies with regard to herbal formulas, control medicine, treatment course, and outcome measurement. The quality of all studies was low. The pooled analyses of effectiveness for the near-term (immediately after finishing the treatment course), short-term (3 months after finishing the treatment course), and long-term (6 months or more after finishing the treatment course) effectiveness showed that the effect of TXYF-A was better than that of conventional medicine in four, two, and six studies, respectively. The RRs were 1.34 (95% CI 1.16-1.54, p < 0.05), 1.39 (95% CI 1.17-1.64, p < 0.05), and 1.34 (95% CI 1.12-1.61, p < 0.05), respectively. Overall, combining all data from the 12 studies, the effectiveness of TXYF-As was higher than that in control groups, with statistical significance and RR of 1.35 (95% CI 1.21-1.50, p < 0.05). Conclusions: There is evidence to indicate the potential usefulness of TXYF-A for IBS patients. The results were limited by the poor quality and heterogeneity of these studies. Further studies with carefully designed, randomized double-blinded placebo-controlled trials will be needed to confirm the effectiveness of TXYF or TXYF-A for IBS.