OBJECTIVE: To explore the bidirectional regulation of acupuncture based on a subgroup analysis of multicenter randomized controlled trial of acupuncture with Tiaoshen Jianpi for irritable bowel syndrome (IBS). METHODS: A total of 519 patients were included in the analysis, including 137 patients with constipation type irritable bowel syndrome (IBS-C) (92 cases in the acupuncture group and 45 cases in the polyethylene glycol [PEG] group), and 382 patients with diarrhea type irritable bowel syndrome (IBS-D) (252 cases in the acupuncture group and 130 cases in the pinaverium group). The patients in the acupuncture group were given acupuncture at Baihui (GV 20), Yintang (GV 29), Tianshu (ST 25), Shangjuxu (ST 37), Zusanli (ST 36), Sanyinjiao (SP 6) and Taichong (LR 3) once every other day, 3 times a week. The patients in the PEG group received polyethylene glycol 4000 powder orally, and the pinaverium group received pinaverium bromide tablets orally. All were treated for 6 weeks. The IBS symptom severity score (IBS-SSS) was assessed at baseline, treatment period (2, 4, 6 weeks of treatment) and 12 weeks of follow-up, and the IBS quality of life (IBS-QOL) score was evaluated at the baseline period, 6 weeks of treatment and 12 weeks of follow-up. RESULTS: The total IBS-SSS scores of the two groups of IBS-C patients at 2, 4, 6 weeks of treatment and follow-up of 12 weeks were lower than those in the baseline period (P<0.01). The total IBS-SSS score in the IBS-C acupuncture group was lower than that in the PEG group at 12 weeks of follow-up (P<0.05). The total IBS-SSS scores of the two groups of IBS-D patients at 2, 4, 6 weeks of treatment and 12 weeks of follow-up were lower than those in the baseline period (P<0.01). The total IBS-SSS scores in the IBS-D acupuncture group were lower than those in the pinaverium group at 2, 4, 6 weeks of treatment and 12 weeks of follow-up (P<0.05). The total IBS-QOL scores at 6 weeks of treatment and 12 weeks of follow-up were higher than those in the baseline period in both groups of patients with IBS-C (P<0.01). The total IBS-QOL scores at 6 weeks of treatment and 12 weeks of follow-up were higher than those in the baseline period in both groups in patients with IBS-D (P<0.01). The total IBS-QOL score in the IBS-D acupuncture group was higher than that in the pinaverium group at 18 weeks of follow-up (P<0.05). CONCLUSION: Acupuncture with Tiaoshen Jianpi can improve the clinical symptoms and quality of life of patients with IBS-C and IBS-D, which can regulate different functional states (constipation and diarrhea) of the same disease (irritable bowel syndrome), reflecting the bidirectional regulation of acupuncture.