Background: Kai-Bi-Bu-Fei Decoction (KBD) is derived from the canonical Traditional Chinese Medicine formulas Xuan-Bai-Cheng-Qi and Ma-Xing-Shi-Gan. It has been employed for decades in the treatment of severe pneumonia with significant clinical efficacy. This study aimed to evaluate the protective effects of KBD against influenza virus-induced severe pneumonia in a murine model and to elucidate the underlying molecular mechanisms. Methods: The chemical profile of KBD was characterized using UPLC-Q-TOF-MS. A severe pneumonia model was established in C57BL/6J mice via intranasal infection with influenza A/Puerto Rico/8/34 (H1N1, PR8). Multiple parameters, including 14-day survival rate, body weight, lung index, histopathological changes, viral load, and pulmonary cytokine/chemokine levels, were assessed. Furthermore, multi-omics analyses were integrated to characterize the gut microbiota and metabolic profiles. Fecal microbiota transplantation (FMT) was subsequently performed to validate the functional role of the gut microbiota and its metabolites. Results: KBD treatment significantly improved the survival rate by 40%, reduced the lung index by 27.85%, and alleviated lung injury. It also markedly lowered the viral load by 80.88%, suppressed pro-inflammatory cytokine levels, and restored intestinal barrier integrity. Mechanistically, KBD restored gut microbiota diversity by increasing the abundance of Firmicutes and Bacteroidetes, enriching beneficial genera such as Bifidobacterium and Faecalibaculum, and reducing Verrucomicrobiota. Integrated transcriptomic and metabolomic analyses revealed that KBD enhanced short-chain fatty acid (SCFA) metabolism and up-regulated pyruvate metabolism. Finally, FMT confirmed that the therapeutic benefits of KBD were transferable via the microbiota to microbiota-depleted mice. Conclusions: KBD exerts robust protection against severe influenza pneumonia, a process primarily mediated by the gut microbiota–SCFA axis. The enhancement of mitochondrial energy metabolism also appears to play a critical role in its therapeutic mechanism.

Background: Bairui granules, a monotherapy derived from Thesium chinense Turcz., are widely used in respiratory tract infections, yet high-quality clinical evidence for their effectiveness in acute bronchitis is lacking. Purpose: To evaluate the effectiveness and safety of Bairui granules in patients with acute bronchitis (Wind-heat invading lung syndrome). Study Design: The study (ChiCTR2200063906) was a multicenter, randomized, double-blind, double-dummy, comparative trial. Methods: Eligible participants from seven hospitals were randomized 2:1 to receive either Bairui granules plus placebo matching Reyanning Granules (experimental group) or Reyanning granules plus placebo matching Bairui Granules (control group) orally for 7 days. The primary endpoint was cough resolution rate after treatment. Secondary endpoints included time to cough and sputum resolution, area under the curve (AUC) for cough and sputum severity, bronchitis severity score (BSS), and traditional Chinese medicine (TCM) symptom scores. Results: Of 162 randomized patients, 161 completed the trial (107 experimental, 54 control). The cough resolution rate was higher in the experimental group than in the control group (72.22% vs. 35.19%; P < 0.0001). The time to cough resolution was 144 h (120,156) versus 168 h (138, 168) ( P = 0.001). AUC for cough severity was 184.3 versus 214.3 score·h ( P = 0.023). The BSS improvement at Day 9 was −4.82 (3.54) versus −4.30 (0.71) ( P = 0.068). The daytime cough TCM score improved by −6 (−6, −6) versus −6 (−6, −3) ( P = 0.003), and the sputum score improved by −3 (−6, −3) versus −3 (−3, −3) ( P = 0.031). Greater improvements were also observed in aversion to wind symptoms (Day 4) and sore throat symptoms (Day 9) in the experimental group. Adverse-event rates were similar between the two groups. All events were mild to moderate in severity and reversible. Conclusion: Bairui granules resulted in a higher cough-resolution rate and faster cough resolution than Reyanning granules in adults with acute bronchitis. The treatment was well tolerated. Clinical Trial Registration: https://www.chictr.org.cn/hvshowproject.html?id=193073&v=1.0 , identifier ChiCTR2200063906.