Obesity is a serious medical problem worldwide. As a holistic therapy, traditional Chinese medicine (TCM) may have a potential in obesity management. In this controlled trial, we evaluated the safety and effectiveness of Xin-Ju-Xiao-Gao-Fang (XJXGF), a TCM herbal formulation, in 140 obese subjects over a 24-week period. The XJXGF formula mainly consists of rhubarb, coptis, semen cassia, and citrus aurantium. Subjects with body mass index (BMI) 28-40 kg/m(2) were recruited at 5 centers in China. We assessed the changes in subjects' body weight, its related parameters, and the reduction of insulin resistance (IR) after administration of XJXGF formula or low-dose XJXGF (10% of the XJXGF formula, as control). After 24-week treatment, among participants in the XJXGF formula group and low-dose XJXGF group, the mean +/- SE changes in the body weight were -3.58 +/- 0.48 and -1.91 +/- 0.38 kg, respectively (p < 0.01). The changes in the IR-index of two groups were -2.65 +/- 1.04 and -1.58 +/- 1.3, respectively (p < 0.05). There were no serious adverse events reported during the 24-week trial. Participants reported 7 minor adverse events, 4 in the XJXGF formula group and 3 in the low-dose XJXGF group (p = 0.578). Future studies are needed to investigate the clinical utility of this TCM formulation in the treatment of obese subjects.