Clonidine, a α2 adrenoreceptor agonist induces dose dependent cata-lepsy in mice, which was inhibited by histamine H1 receptor antagonists but not by H2 receptor antagonist. Clonidine releases histamine from mast cells which is respon-sible for different asthmatic conditions. Clitoria ternatea L. (Family: Fabaceae) is a per-imial twing herb. The roots have anti-inflammatory properties and are useful in severe bronchitis, asthma. In present study ethanol extract of Clitoria ternatea root (ECTR) at doses 100, 125 and 150 mg/kg i.p were evaluated for antihistaminic activity using clonidine and haloperidol induced catalepsy in mice. Finding of investigation showed that chlorpheniramine maleate (CPM) and ECTR inhibit clonidine induced catalepsy significantly P < 0.001 when compare to control group, while CPM and ECTR fail to inhibit haloperidol induced catalepsy. Present study concludes that ECTR possesses antihistaminic activity.