Objective To explore the correlation between food allergies and duodenal mast cells in pathogenesis with functional dyspepsia (FD).Methods The symptoms of FD were scored in 48 patients with FD,which included 23 patients with postprandial distress syndrome (PDS) and 25 patients with epigastric pain syndrome (EPS).The specimens of duodenal and descending part of duodenum mucosa were obtained under gastroscopy in 48 FD patients and 21 healthy volunteers,and 3 mL venous blood was taken at same time.The percentages of mast cells and degranulated mast cells were calculated after the specimens were stained by toluidine blue.The serum specific IgG antibodies of 14 food allergies were detected by enzyme-linked immunosorbent assay.Two-sample comparison was performed by t test,LSD-t-test for groups' comparison,chi-square or Fisher’s exact test for rates comparison and Pearson linear correlation for correlation analysis.Results The number of mast cells in duodenal and descending part of duodenum of FD group,PDS group and EPS group was significantly higher than that of control group and the differences were statistically significant (duodenal:t =3.387,3.536 and 3.510; descending part of duodenum:t=5.810,4.400 and 3.813; all P＜0.01).In duodenal and descending part of duodenum,the percentages of degranulated mast cells in all mast cells of FD [(60.23± 5.10)％ and (66.97±5.30)％],PDS [(59.84±4.50)％ and (66.63±5.37) ％] and EPS [(60.58±5.66) ％ and (67.28±5.32) ％] were all higher than those of control group [(25.38 ± 2.32％) and (30.66 ±2.89)％],and the differences were statistically significant (duodenal:t=33.639,25.496 and 26.563; descending part of duodenum:t=32.513,30.521 and 31.612; all P＜0.05).There was no correlation between the number of mast cells,percentage of degranulated mast cells in duodenal or descending part of duodenum and the scores of symptoms (all P＞0.05).In PDS group,the rates of positive specific IgG antibodies of beef,crab,shrimp,wheat and chicken were significantly higher than those of control group,and the differences were statistically significant (beef x2=12.108,crab x2=17.771,shrimp x2=6.832 and wheat x2=4.375,chicken (Fisher’s exact test); all P＜0.05).In EPS group,the rates of positive specific IgG antibodies of beef,soy and chicken were significantly higher than those of control group,and the differences were statistically significant (beef x2 =8.915,soy x2 =18.600,chicken (Fisher' s exact test) ; all P ＜0.01).The scores of positive specific IgG antibodies of food allergies and types of FD,PDS and EPS were significantly higher than those of control group,and the differences were statistically significant (the score of positive IgG:t=14.988,4.062 and 3.693; the positive type of IgG:t=8.805,4.177 and 3.388; all P＜0.01).The scores of positive specific IgG antibodies of food allergies and types were positively correlated with the number of mast cells and the percentage of degranulated mast cells in duodenal part of duodenum (the score of positive IgG:r=0.247 and 0.307,the positive type of IgG:r=0.243 and 0.326; all P＜0.05).Conclusion The specific IgG antibody of food allergies might play a role in the pathogenesis of FD through inducing an increase in the number of mast cells and the percentage of degranulated mast cells in duodenal mucosa.