Introduction & Objective: Locomotor activity is an important physiologic phenomenon that is influenced by several factors. In previous study we showed that the matricaria chamomilla (chamomile) hydroalcholic extract acts differently in male and female mice. Therefore in this study, the role of sex hormones and chamomile hydroalcholic extract were investigated on motor activity behavior in absence of sex glands in adult male and female NMRI mice.

Materials and Methods: Gonadectomized male and female mice were divided into groups (seven mice in each group) including: receiving testosterone (2 mg/kg S.C.), estradiol benzoate (0.1 mg/kg S.C.), and progesterone (0.5 mg/kg S.C.) with and without hydroalcholic extract of chamomile (50 mg/kg i.p). Motor activity monitor system was used to evaluate locomotor activity parameters (fast and slow activity, fast and slow stereotype activity, fast and slow rearing) in all groups. 

Results: 1) Testosterone had no any effect on motor activity parameters, but extract of chamomile with and without testosterone decreased motor activity parameters in male mice. 2) Estradiol benzoate and chamomile hydroalcholic extract in presence and absence of each other increased locomotor activity parameters in female mice. 3) Progesterone also did not change motor activity parameters in presence and absence of chamomile hydroalcholic extract in female mice. 4) Administration of Estradiol benzoate with progestrone in presence and absence of chamomile hydroalcholic extract did not alter motor activity parameters in female mice.

Conclusion: It seems both of the chamomile hydroalcholic extract and estradiol enhance motor activity and probably act through same system and potentiate the effect of each other. Also it seems there are interaction between estradiol and progesterone and also between chamomile extract and progesterone. Testosterone probably did not have any interaction with chamomile extract in locomotor activity.