AIM: To investigate the effect of platelet activating factor (PAF) on the content of secretory IgA (SIgA) in intestinal mucosa. METHODS: The rats were intraperitoneally injected with different concentrations of PAF (50 and 65 μg/kg) at a dose of 1 μL/g. Double antibody-PEG radioimmunoassay was used to determine the amount of SIgA in the intestinal mucosa. The histological changes were detected by hematoxylin and Eosin staining under light microscope. RESULTS: In the PAF65 group, the histological examination showed edema of the villus, capillary congestion of the lamina propria, extension of the subepithelial lymphatic channel, polymorphonuclear infiltration in enteric cavity, and shedding of the epithelial layer at 0.5, 1.5, and 3 h. Edema of the villus were still shown at 6 and 24 h. In the PAF50 group, edema of the villus, capillary congestion of the lamina propria were showed at 0.5 and 1.5 h. Edema of the villus were still shown at 3, 6 and 24 h. The content of SIgA was obviously decreased in the experimental group than that in the control group (0.31±0.03 mg/L, 0.40±0.10 mg/L, P <0.01; 0.43±0.13 mg/L, 0.46±0.11mg/L, P <0.05, in PAF50 group; 0.28±0.07 mg/L, 0.36±0.08 mg/L, P <0.01, 0.40±0.11 mg/L, 0.42±0.06 mg/L, P <0.05, in PAF65 group vs 0.66±0.10 mg/L in the control) at 0.5, 1.5, 3 and 6 h, respectively. The SIgA content decreased most at 0.5 h, but then gradually increased. CONCLUSION: PAF can lead to damages of the intestinal immunologic barrier by decreasing the SIgA content.