A healthy pig shows significant eosinophil infiltration in the lamina propria of the small intestine. Although the exact role of these infiltrated eosinophils in healthy pigs is unclear, eosinophil infiltration is a well-known phenomenon that is frequently observed during an allergic status. Alpha-linked galactooligosaccharide (GOS) reduces eosinophil infiltration into broncho-alveolar lavage fluid of an allergic airway eosinophilia model. We evaluated the effect of GOS oral administration on the suppression of eosinophil infiltration in the small intestine of healthy weaned pigs. Nine 21-day-old pigs were purchased and divided into three groups. One group was fed the basal diet supplemented with sucrose at 0.11% (C), one group was fed the basal diet supplemented with GOS at 1.17% (GOS A) and one group was fed the basal diet supplemented with GOS at 0.03% (GOS B). Each group was fed its respective diet throughout this study (10 days). The daily body weight gain from d3 to d10 was significantly bigger in the GOS B group than in the other groups. The feed conversion ratios from d0 to d10 were two times lower in the GOS B group than in the C group. Dietary GOS suppressed eosinophil infiltration in the small intestine. However, GOS administration had no effect on the organic acid level or microbial composition in the small and large intestinal digesta.