Background and Objectives: Phenylhydrazine (PHZ), as a known hemolytic agent, causes toxicity in different tissues at various levels. The aim of the current study was to examine the possible protective effects of royal jelly (RJ) against PHZ-induced histological injuries of small intestine in mice.   Methods: In this experimental study, adult male mice were randomly divided into four groups of 8 mice each. PHZ was administered intraperitoneally to two groups of mice (at a dose of 60mg/kg) every 48 hours for 35 days. One of the groups received RJ (100mg/kg) orally 4 hours before PHZ administration. The third group only received RJ, and the forth group was considered as control. Twenty-four hours after the last treatment, different segments of small intestine were dissected out, then histological sections were prepared and quantitative morphometric assessments were performed. To compare the groups, one-way ANOVA and multiple comparative Tukey tests were used. The significance level was considered to be p<0.05.   Results: In this study, PHZ caused significant decreases in depth of duodenal crypts, distribution rate of the goblet cells in ileal villi, width of duodenal and jejunal villi, and height of villi in all three segments of small intestine. Co-administration of RJ partially improved the changes in the above parameters.   Conclusion: From results of this study, it seems that RJ as a free radical scavenger could reduce PHZ-induced intestinal toxicity in mouse.