BACKGROUND AND AIM: The treatment of patients with functional dyspepsia (FD) remains unsatisfactory. We assessed the efficacy of Zhizhu Kuanzhong (ZZKZ) capsule, a traditional Chinese medicine formula, in patients with postprandial distress syndrome (PDS) of FD. METHODS: The study was designed as a multicenter, randomized, double-blinded, controlled clinical trial. Three-hundred ninety-two patients with PDS defined by Rome III criteria from 16 centers in China were randomly assigned to receive either ZZKZ or placebo. The proportion of the responders at 4 weeks after randomization was considered primary endpoint. Secondary endpoint was the symptom score reduction of each dyspeptic symptom relative to the baseline at 4 weeks after randomization in all subjects. RESULTS: In terms of the primary endpoint, the proportion of the responders concerning the composite PDS symptom score was 38.8% and 54.7% in placebo group and ZZKZ group, respectively (P = 0.003), in per protocol analysis at 4 weeks after randomization. Concerning the individual evaluated upper gastrointestinal symptoms, only postprandial fullness and early satiety showed significant difference in symptom score reduction at 4 weeks after randomization between placebo and ZZKZ groups. CONCLUSIONS: Zhizhu Kuanzhong is superior to placebo in the treatment of PDS with FD. The exact mechanisms by which ZZKZ improves symptoms remain to be established (http://www.chictr.org.cn/ChinCTR-TRC-14004714).