Non-alcoholic fatty liver disease (NAFLD) is associated with a high morbidity in patients with impaired fasting glucose (IFG). Bicyclol is a synthetic compound known to protect the liver against oxidation and lipid injuries. The objective of this study was to evaluate the efficacy and safety of metformin and bicyclol in the treatment of NAFLD patients with IFG. After lifestyle changes and metformin treatment (500 mg orally three times daily), the 248 patients enrolled with NAFLD and IFG were equally randomized to two 24-week treatment groups: bicyclol 25 mg three times daily or vitamin E (alpha-tocopherol) 100 mg three times daily (control). Anthropometric measurements, serum biochemistry, liver/spleen computed tomography ratio, and changes in liver histological parameters were compared before and after treatments. A total of 223 patients completed the treatment, and there were significant improvements in body mass index, waist-to-hip ratio, and biochemical parameters in both groups (P < 0.01). Compared with the control group, the improvement in serum alanine aminotransferase levels in the bicyclol group was statistically significant (P < 0.01). Liver histological assessments revealed that steatosis, inflammation, hepatocellular ballooning, and NAFLD activity scores (NAS) were all decreased in both groups after treatment (P < 0.01). However, decreases in inflammation and NAS in the bicyclol group were statistically significant compared with the vitamin E group (P < 0.01). Adverse events in the bicyclol and control groups occurred in 1.79 and 1.80 %, respectively. Metformin combined with bicyclol is effective and safe in the treatment of patients with NAFLD and IFG. However, further studies with a larger sample size are needed to confirm the efficacy and safety of the combination.