BACKGROUND: Traditional Chinese medicines, as a burgeoning field of medication, significantly alleviate ulcerative colitis (UC) by improving intestinal microbiota-metabolism. Our previous studies demonstrated the significant efficacy of Hudi Enteric-coated capsules (HDEC), Qingchang Wenzhong decoction (QCWZ), and Modified Wumei pill (MWMP) using a mouse model of colitis. However, the mechanism of these therapies through the modulation of microbiota-metabolism remains uncertain. OBJECTIVE: Three multicenter randomized controlled trials were designed to explore the effects of three therapies on the microbiota-metabolism of UC patients with different severity. METHODS: A total of 143 patients with different severities of UC were recruited from 10 hospitals. The clinical efficacy of HDEC for mild UC, QCWZ for moderate UC, and MWMP for severe UC (SUCs) was evaluated by colorectal Mayo scores and systemic inflammatory indicators. The 16S rRNA sequencing and metabolomics were used to analyze intestinal microbiota and metabolite profiles. RESULTS: Three therapies used alone or combined with mesalazine (MS) were comparable to MS alone in improving Mayo scores and hematic inflammatory parameters. Microbial diversities and architectures of SUCs showed the greatest response to MWMP+MS than other medications, as reflected by the enriched Ruminococcus and Anaerostipes together with the reduced Enterococcus, Streptococcus, and Streptococcus anginosus. Furthermore, MWMP+MS boosted the production of the microbiota-derived short-chain fatty acids (SCFAs) of SUCs. These differential microbes and metabolites further displayed significant statistical relationships with clinical parameters. CONCLUSION: Herbal therapies, especially MWMP+MS, effectively improve microbiota composition and SCFA metabolism, which correlates with the improvements of serum inflammatory markers and endoscopic findings in patients.