Introduction:Synbiotics have beneficial effect on intestinal inflammation and permeability (1, 2, 3). We aimed to analyze the effect of long term (4 months) synbiotic treatment on non‐alcoholic fatty liver disease (NAFLD) in obese children.Patients and Methods:The study included the 28 children with NAFLD (12.2 ± 2.2 years and 64.3% male) based on the clinical and liver ultrasound (US) findings (severe fatty liver in 25%, moderate in 57% and mild in 18%) and 28 age‐and sex matched healthy children. At baseline, patients and control group underwent anthropometric measurements including body mass index (BMI) and laboratory evaluation including liver function tests, serum lipids, HOMA‐IR, cytokeratin‐18 (CK‐18), ethanol, tumor necrosis factor alpha (TNF‐α), oxidant (TOS) and anti‐oxidant (TAS) and zonulin levels and stool calprotectin level. All the patients with NAFLD were treated with synbiotics including Bifidobacterium lactis, Lactobacillus acidophilus and Lactobacillus casei (7 million CFU/day) plus inulin 100 mg (Maflor plus capsules®), 1 capsules per day for 4 months. Clinical and laboratory analysis was repeated in patients 4 months after synbiotic treatment and the results were compared with baseline and control group.Results:Apart from anthropometric measurements; liver function tests and lipid profile, serum ethanol (4.9 ± 3.9 vs. 0.6 ± 0.8 mg/dl, p = 0.001), TNF‐α (9.9 ± 7.4 vs. 6.1 ± 4.6 pg/mL, p = 0.03), and stool calprotectin level (14.1 ± 17.4 vs. 7.2 ± 0.8 ng/mL, p = 0.01) were significantly high in patients with NAFLD compared to healthy children. After treatment, improvement in anthropometric parameters was seen in all patients. Significant decrease was found in liver function tests, serum ethanol (4.9 ± 3.9 vs. 0.9 ± 1.4 mg/dl, p = 0.001) and TNF‐α (9.9 ± 7.4 vs. 8.4 ± 7.4 pg/mL, p = 0.01) levels and stool calprotectin level (14.1 ± 17.4 vs. 7.9 ± 1.5 ng/mL, p = 0.04) after treatment, whereas serum TAS levels (1.4 ± 0.3 vs. 1.8 ± 0.4 mmol trolox Eq/L, p = 0.02) were significantly increased. Liver US revealed severe fatty liver in 14.3%, moderate in 39.2%, mild in 39.2% and normal in 14.3% of the patients. Liver US findings were improved in 19 patients (67.8%) when compared to baseline US findings. It was found that ethanol (5.3 ± 4 vs. 0.9 ± 1.47 mg/dl, p = 0.001), TNF‐α (9.6 ± 7.1 vs. 5.5 ± 3 pg/mL, p = 0.026) levels, BMI (30.5 ± 6.6 vs. 28.6 ± 6.1 kg/m2, p = 0.001) were significantly decreased and TAS levels (1.4 ± 0.3 vs. 1.8 ± 0.3 mmol trolox Eq/L, p = 0.03) were significantly increased compared to baseline findings in the US improved group (n = 19), whereas significant differences were observed in only ethanol (5.8 ± 4 vs. 1.1 ± 1.3 mg/dl, p = 0.01) and TAS (1.2 ± 0.3 vs. 2.2 ± 0.4 mmol trolox Eq/L, p = 0.02) levels in patients without any US improvement (n = 9).Conclusion:Synbiotics are effective for the treatment of NAFLD in children, and it may be related with the effect of synbiotics on inflammation (decrease in TNF‐α level) and BMI.