In this meta-analysis, 4 studies of the 15 included studies used Friedewald’s formula to calculate LDL-C concentrations, and the remaining 11 studies used direct measuring method to Nutlin-3 detect LDL-C concentrations. However, the mean triglycerides concentrations of the subjects in the four studies ranged from 93 to 275 mg/dL, which may not be considered as highly abnormal. It has been demonstrated that the results of direct measuring method of LDL-C and the Friedewald’s formula were highly correlated when the TC concentrations ranged from 60 to 308 mg/dL. Therefore, we did not exclude the studies using Friedewald’s formula to calculate LDL-C concentrations and perform further analysis to investigate the influence of triglycerides concentrations on the meta-analysis on LDL-C concentrations. Although we believe that this study provides useful findings, several inevitable limitations should be addressed. First, of the 15 studies, only 4 were identified as high-quality RCTs by Jadad scoring criteria, whereas the remaining 11 were of low-quality. This is mainly due to that 9 of 15 included studies used water as placebo in the control group, which is difficult for the researchers to conduct double-blinding. Second, only one study provided the same background controlled diet to both intervention and control group during the study period. Most of the studies only suggested the participants keep their usual diet and limit consumption of black tea, caffeine, or polyphenols, etc. Due to the wide range and distribution of polyphenols in foods and drinks, the precise control of dietary intake in the original studies including free-living subjects was impossible. The differences in background dietary intake might bring confounding factors that affect the current results of this meta-analysis. Third, we cannot independently conduct meta-analyses to explore the effect of black tea polyphenols on blood cholesterol concentrations because caffeine is naturally existed in black tea and there is limited information about the content of caffeine in most of the included studies. Therefore, it is hard for us to evaluate the potential confounding effect of caffeine on cholesterol concentrations. In addition, it is difficult for us to evaluate the interaction between black tea consumption and medicine use in subjects with diabetes or coronary artery diseases. However, none of the included studies reported significant unsafe effects of black tea on included participants. Moreover, measures of cholesterol were not the primary outcome in part of the RCTs reviewed in the metaanalysis and the null findings of secondary outcomes may not always be published. In conclusion, this meta-analysis showed that black tea consumption may have no significant effect on TC, HDL-C, and LDL-C concentrations. Further high quality RCTs are needed to definitively draw a causal interpretation of the findings. The prevalence of diabetes.