Introduction & Objective: Medicinal plants are widely used throughout the world. Hypothyroid-ism is an important hormonal disease that causes some disorders in body organs. Salvia officinalis has been known as a medicinal plant since ancient times. In this study the Salvia offi-cinalis extract (SOE) effects on thyroid hormones and TSH in hypothyroid rats have been investigated.

 Materials & Methods: In this experimental study the SOE extract was prepared and 40 male rats were randomly divided in five groups. Control, propylthiouracil (PTU) in 4 groups + SOE. The animals were induced hypothyroidism by administration of PTU 0.1% orally in tap water for 14 days. The blood samples were collected and T3 & T4 and TSH hormones were analyzed. Hypothyroid groups were divided into 4 groups and received (PTU+ SOE 40 mg/kg +levothyroxine sodium, 15mcg/kg, orally in tap water) and LV+ SOE). All test groups were treated with SOE and levothyroxine sodium for one week. The blood samples were collected and for T3 & T4 and TSH hormones were analyzed at the end of the 3rd week. All data were expressed as mean ± SEM and all statistical procedures were performed by MANOVA test.

Results: Our results showed that the T3 & T4 plasma levels in hypothyroid animals treated by SOE had significant differences (P<0.05) compared with the control group.

Conclusion: Our findings suggest that the SOE has stimulatory effect on thyroid gland function and raises plasma T3 & T4 levels.