In Ayurveda, Euphorbia thymifolia L. (Euphorbiaceae) prescribed in the treatment of various ailments like bronchial asthma, cough, diarrhea and bleeding piles. The present study was investigated to evaluate antianaphylactic, mast cell stabilizing and antiasthmatic activity of methanol and aqueous extract of E. thymifolia (ET) on experimental animals. Anaphylaxis was induced by administration of horse serum and triple antigen vaccine intraperitoneal (i.p.) in albino Wistar rats. Extracts of ET were administered to the rats in dose of 250 and 500 mg/kg orally for 14 days. At the end of treatment, asthma score was measured and various blood parameters like differential count (DC), total WBC count and IgE were estimated. Interleukin (IL)-4, IL-5 and TNF-α were measured by ELISA commercial kit from BALF. Histopathological changes of lungs were observed. Antiasthmatic activity of extracts of ET was also studied on histamine-induced bronchospasm in guinea pigs. In vitro mast cell stabilizing activity of extracts was evaluated on compound 48/80 challenged rat intestinal mesenteric mast cells. The treatment with extracts of ET produced significant decrease in asthma score and they also brought to normalcy the increased total WBC, DC counts, serum IgE, TNF-α, IL-4 and IL-5 in BALF. The histopathological study further supported the protective effect of ET extracts. The pretreatment with extracts of ET displayed significant reduction in degranulation of mesenteric mast cell numbers. The treatment with extracts of ET significantly increased in time of PCD. Thus, these findings concluded that E. thymifolia could be effectively used in the treatment of anaphylaxis and asthma. Keywords: Euphorbia thymifolia, IgE, TNF-α, IL-4 and IL-