Hypothyroidism happens when thyroid gland doesn't make enough thyroid hormones to meet the body need. This study aimed to investigate the effect of some levels of alcoholic extract of Saussurea Costus (S. costus) root on Propylthiouracil induced hypothyroidism in rats. Thirty-five rats were divided into two main groups as follows: the first main group (7 rats) control negative group. The second main group, 28 rat were injected with Propylthiouracil (PTU) then were divided into 4 subgroups (7 rats each), fed on basal diet and were given orally (100, 300 and 500 mg Alcoholic Extract of root Saussurea /kg BW), respectively. The results showed that rats injected with Propylthiouracil (positive control rats) had significant (P <0.05) decrease in the concentrations of thyroxine (T4) and triiodothyronine (T3), Iodin, Iron, Zinc, Selenium and Vitamin C and significant increase in thyroid-stimulating hormone (TSH) level as compared to that of the negative control group. It was also observed that the oral alcoholic extract of (S. costus) root caused a significant (P<0.05) improvement in the thyroid functions as increasing the concentrations of FT3, FT4 and lowering the level of TSH. Moreover, the level of lipid profile was decreased as well as the biomarkers of oxidative stress as compared to the positive control group. The level of Iodin, Iron, Zinc, Selenium and Vitamin C as well as the concentrations of antioxidant biomarkers were significantly increased as a result if giving oral alcoholic extract of (S. costus) root. The current investigation revealed that administration of PTU to rats was related to abnormalities levels of thyroid hormones, and oxidative stress parameters and that therapy with alcoholic extract of (S. costus) root ameliorated these variations in blood, suggesting alcoholic extract of (S. costus) root may be suitable for improving the functions of thyroid gland.