Abstract Lavandula officinalis is a plant with many unknown effects on organism physiology. Previous articles about it were focused on some available and routine effects on brain and not specifically about other physiological realities. This study examines effect of hydroalcoholic extract of Lavandula officinalis on thyroid hormones. In this study 50 mature mice (Balb/C) were applied. They treated with Lavandula officinalis hydro alcoholic extract in three doses. 50,100 and 200 mg/kg, and two groups of them were control group without any injection and placebo group with normal saline injection. After 20 days (10 times every other day) blood was taken. After that serum of every tube has separated and TSH, T3 and T4 were measured by auto analyzer apparatus. Data were analyzed with SPSS and Excel software and t-student test. The results indicated that lavender hydro alcoholic extract caused increased some thyroid hormones. It was proved that thyroxine (T4) hormone was increased compared with control group while T3 and TSH concentration did not change. Based on the results obtained in this study, the extract can be dose-dependently effective in the activity of the thyroid gland and increase the secretion of thyroid hormones. These changes can have several adverse physiological effects.
Keywords Lavender, T4, T3, TSH, Mice.