Rosmarinic acid (RA) is an active polyphenol that is widely found in various edible herbs. This study was to explore the potential anti-allergic activities and the underling mechanisms of RA on ovalbumin (OVA)-induced intestinal allergic mice.Forty female BALB/c mice were randomly divided into five groups: control group, model group (OVA sensitized/challenged), RA-Low group (OVA sensitized/challenged, 30 mg/kg RA intervention), RA-Middle group (OVA sensitized/challenged, 90 mg/kg RA intervention) and RA-High group (OVA sensitized/challenged, 270 mg/kg RA intervention). RA effectively attenuated the allergic reactions, including alleviating the allergic symptoms and regulating the hypothermia of mice in the model group. Moreover, the anaphylactic mediators (OVA specific IgE (OVA-sIgE), histamine and mMCP-1) levels of OVA allergic mice were remarkably decreased after RA intervention. The q-PCR analysis showed that RA significantly inhibited the Th2 cytokines expression, while the Th1 and Treg cytokines were remarkably increased. 16S rRNA gene sequence analysis indicated that RA effectively regulated the richness and diversity of the intestinal microbiota in OVA allergic mice. In the phyla level, the relative abundance of Bacteroidetes and Firmicutes and the Firmicutes/ Bacteroidetes ratio were altered by RA intervention. In the genus level, RA showed to regulate the disturbances in the relative abundance of Muribaculaceae, Lactobacillus and Prevotella.RA exhibited potential anti-allergic activity in OVA allergic mice by regulating hypersensitive immune responses and the intestinal microbiota structure. These provide important evidence that RA can be developed into a novel functional food derived ingredient against food allergy. This article is protected by copyright. All rights reserved.This article is protected by copyright. All rights reserved.