Dimethoate, an organophosphate pesticide, is used in controlling the pests of a variety of crops. Herbal medicine is the most widely used form of medicine in the world today where the medicinal plants contain many curative bioactive ingredients. The present work was planned to evaluate the potential protective effect of Enchinacea purpurea (EP) against the immunotoxic effect induced by dimethoate in adult male albino rats. Rats were classified into four groups (10 in each). Rats in the 1^st group received no treatment and served as control. Rats in the 2^nd group were orally administered dimethoate 40%EC in a dose level of 3mg / kg bw. Equivalent to 1/10 LD50. Rats in the 3^rd group were Orally administered EP (Immulant) in a dose level of 2.5 ml/kg bw. The fourth group was treated with dimethoate 40%EC as in group II in addition to EP dose level as in the third group. Administration of tested substances was carried out daily for Successive 7 days. Rats from treated as well as from control group were injected IP with (1-2x 10⁸) sheep RBCs as non specific antigen. After 7 and 14 days from injection of sheep RBCs (SRBCs) five rats from each group were taken, blood and tissue samples were collected. The present data revealed a significant decrease in WBCs count (leucopenia), neutrophillia and lymphocytpenia with lower haemagglutination inhibition antibody titre (HI) and significant decrease in IgM in serum samples from dimethoate treated rats. Also in the same group there was a significant decrease in serum thymus were recorded in dimethoate treated group.  EP supplementation induced group. appreciable improvement in all previous abnormal alterations observed in dimethoate treated rats. Therefore, this study revealed that EP exhibit marked protective role against the toxic effect of dimethoate on immune system of male albino rats.