e 553 nt nuclear m nagneti ce-dp that the early onse 以o tabolism by degradati of cholin from the gut of morbidly obese and diabetic on dir ethe showing that GOD can modulate ota microbiota,particularly in hum doubl-blinded placebo-co oled clinical tria metabolic dis made to target the xamined the structura rine (Khin 28 1987 efficacy Materials and methods olled clinical tria tudy desig he was a 12-week.randor ized.double period.It was ap rove ea control for te Our h-fat ang'anmen hospita and insulin stanc anmen hosp pital,Dong Zhimen Hospita Beijing fron l partic ed in that treat bacterial diarrhea such a wa conducted in erberin might be useful treatment with the principles of the Declaration biota. Chin The inclusion and exclusion criteria of the has at can methods.Usi品n Its reco ed by SC reening,including FBG test 219).Su tand 75-02 nha atment for T2D were recruite into the stud observat eries of examinations.403 patients were excluded reduce glu s Th ia and?2 diabetic SD high (HD).mo one (MD)or low (LD)GQD.or the placebo for 12 weeks was low-dose treat Tonstd ies are clinical investigations with small sample The ISME Journalhealthy controls showed that diseased samples had lesser abundance of butyrate-producing bacteria, such as Faecalibacterium prausnitzii, but greater abundance of opportunistic pathogens, including Clostridium bolteae and Desulfovibrio sp. (Qin et al., 2012). Another study found that the early onset of high-fat-diet-induced T2D was characterized by an increased bacterial translocation from the intestine towards tissues (Amar et al., 2011). An opportunis￾tic pathogen, Enterobacter cloacae B29, isolated from the gut of a morbidly obese and diabetic patient, induced obesity and insulin resistance in germ-free mice (Fei and Zhao, 2013). Taken together, these studies indicate that a dysbiotic gut microbiota may causatively contribute to obesity and diabetes development, and thus may serve as a potential new target for disease control. To treat obesity, T2D and other metabolic diseases, several attempts have been made to target the gut microbiota (Cani et al., 2007b, 2009; Park et al., 2013). Berberine, the major pharmacologic compo￾nent of a Chinese herb Coptis chinensis (Huang￾Lian) originally used to treat bacterial diarrhea (Khin Maung et al., 1985; Rabbani et al., 1987; Tang et al., 2009), showed clinical efficacy in treating diabetes in a multicentered, randomized, double-blinded and placebo-controlled clinical trial (Zhang et al., 2008). The herb C. chinensis has been used in traditional Chinese medicine (TCM) for diarrhea control for nearly 2000 years. Our recent study showed that berberine prevented high-fat￾diet-induced obesity and insulin resistance, enriched short-chain fatty acid-producing bacteria, reduced numbers of opportunistic pathogens and alleviated inflammation in Wistar rats (Zhang et al., 2012b). Drugs that treat bacterial diarrhea, such as berberine, might be useful for T2D treatment because both diseases share a dysbiotic gut micro￾biota. A standardized berberine-containing Chinese herbal formula, Gegen Qinlian Decoction (GQD), has been a treatment for diarrhea in Shang Han Lun since the East Han Dynasty. Its use was recorded by the prestigious physician Zhongjing Zhang (AD 150– 219). Subsequently, GQD has been reported to have potentially beneficial effects in the treatment of diabetes in animal trials, as well as in some clinical observations. For example, GQD significantly reduced fasting blood glucose (FBG) and glycated hemoglobin (HbA1c) in streptozotocin (STZ) and high-fat-diet-induced diabetic SD rats, and the serum of SD rats that received GQD enhanced glucose consumption in 3T3-L1 adipocytes (Zhang et al., 2013). T2D patients treated with a high dose of modified GQD two times daily for 3 months showed a reduction in HbA1c of 1.79% from the initial level of 9.2%. This decrease was significantly different from that of patients receiving a low-dose treatment (Tong et al., 2011). However, these studies are either animal trials or open, non-placebo-controlled clinical investigations with small sample sizes. Moreover, the mechanism underlying GQD’s impact on glycemic efficacy has barely been elucidated. A recent nuclear magnetic resonance-based plasma metabonomic study revealed that 5 weeks of GQD treatment conspicuously modulated gut microbial metabolism by degradation of choline into methyla￾mines, together with a decrease in FBG and an expansion of islets in STZ and high-fat-diet-induced diabetic rats (Tian et al., 2013). This finding indicates that the gut microbiota might have a pivotal role in the effect GQD has on diabetic subjects. However, there is still a lack of direct evidence showing that GQD can modulate gut microbiota, particularly in humans. In this study, we conducted a randomized, double-blinded, placebo-controlled clinical trial to evaluate the efficacy and safety of GQD in the treatment of T2D. Furthermore, we examined the structural alterations of gut micro￾biota in response to GQD treatment intended to alleviate T2D. Materials and methods Study design The study was a 12-week, randomized, double￾blinded and placebo-controlled clinical trial that included a 2-week washout period. It was approved by the Ethics Committee of Guang’anmen hospital of China Academy of TCM. Participants were recruited by Guang’anmen hospital, Dong Zhimen Hospital affiliated to Beijing TCM University, China–Japan Friendship Hospital or Ji Shui Tan Hospital of Beijing from August 2010 to May 2011. All partici￾pants signed informed consent forms before begin￾ning the study. The study was conducted in accordance with the principles of the Declaration of Helsinki. The inclusion and exclusion criteria of the patients’ enrollments can be found in the Supplementary Materials and methods. Using an initial screening, including FBG test and 75-g oral glucose tolerance test, 629 recently diagnosed T2D patients who had not received prior pharmacologic treatment for T2D were recruited into the study. After a 2-week washout period and the review of a series of examinations, 403 patients were excluded for not meeting the inclusion criteria and 2 patients were excluded for other reasons. The remaining 224 patients were randomly assigned to four groups of 56 patients. Each group received one of the follow￾ing treatments: high (HD), moderate (MD) or low dose (LD) GQD, or the placebo for 12 weeks. Randomization was performed centrally and was concealed and stratified in blocks of eight by the PROC PLAN process using the SAS software (SAS Institute Inc., Cary, NC, USA). After the study was completed, a total of 187 patients were included for the final analysis by the verification of data examination committee (Supplementary Figure 1). Microbiota shift in alleviation of type 2 diabetes J Xu et al 553 The ISME Journal