This experiment was conducted at poultry field in the Agriculture College-Al-Muthana University during the period from 15/10 /2015 until 22/ 11/ 2015. It was used 240 of broiler chicks Ross 308, chicks were randomly distributed to four experimental treatments, where added the aqueous extract of thyme leaves at levels (0, 2, 4, 6 ml/L) drinking water. All of the histological traits were studied such as the villus height, the crypts depth , the percentage of the villus height to the crypts depth and immunological traits are both the immunity directed against Newcastle disease and the test of the relative hypersensitivity in thewattles and relative weight and the Fabricia gland index and the blood traits are both the number of red and white blood cells and volume of the blood packing cells (Haematocrit) and Hemoglobin concentration, and biochemical traits, such as concentration of glucose, cholesterol, triglyceride, globulin, albumin, and total protein. The results showed a significant improvement (P≤0.05) for the treatment of the aqueous extract of high concentration thyme leaves (6 ml/L drinking water) in all studied traits compared to all study treatment Keywords | Aqueous extract, Thymus vulgaris, Small intestine tissue, Immunological, Blood traits, Broiler chicks. Jassim Kassim menati 1 , nihad abdul-lateef ali 2* , hassan saad abidelhuseen 3