Background: Khat (Catha edulis Forsk) is one of the psycho stimulant plant and about 20 millionrnpeople consume khat leaves around the world. It contains many different compounds and inducesrndozens of effects mainly on the gastro-intestinal, cardiovascular and nervous systems.rnObjectives: This in vivo random experimental animal study was conducted to evaluate the acute dose-rnand time- responses of crude Catha edulis extract on a) Serum electrolytes, locomotors activity andrnanxiety-like behavior in mice and b) Mesenteric blood flow velocity in guinea pigs.rnMethodology: On mice (n=60), the acute dose- and time- responses of crude Catha edulis extract onrnserum electrolytes were measured by ion selective electrolyte analyzer. Serum was collected after thernonset of 45, 90 and 180 minutes of oral administration of 100, 200 and 400mg/kg doses. The locomotorsrnand anxiety- like behaviors were tested in mice in the same dose of the above test and submitted to lightrn/dark box activity test for an hour after oral administration. Data were acquired by the surveillance videorntracking data acquisition system. In guinea pigs (n=10), superior mesenteric blood flow velocity wasrnmeasured by Ultrasound Doppler flow meter. This was tested by placing its flow meter probe (4 Hz)rnbetween 45 and 60 degrees on superior mesenteric blood vessels. Blood flow velocity was recordedrndigitally for half an hour following normal saline administration as baseline; while 0.2ml Catha edulisrnextract solution infusion as treatment and recorded for 1hour.rnResults: The electrolytes acute study results had shown insignificant variation in Na+, K+, Ca2+, and Cl-.rnLocomotors and anxiety-like behavioral acute study result had shown an increase in motor activity, andrninduce anxiety-like behaviors following the initial 15 to 20 minutes of anxieolytic-like effects withrnrespect to dosage(4 groups, n=6 for each group). While, the acute hemodynamic study result had shownrnsignificant increased systolic and diastolic blood flow velocities in response to Catha edulis extractrninfusion as compared to the base line.rnConclusion: The insignificant variation in Na+, K+, Ca2+, and Cl- may be related to rapid and sensitivernregulatory mechanisms that keeps electrolytes in balance through active and passive transport of ions.rnThe increased locomotors activity is more likely induced by Catha edulisâ€™s ability to enhancerndopaminergic transmission from dopaminergic neurons like substantial nigra compacta to striata of thernbasal ganglia and retarding DA reuptake effect of Cathinone. The initial anxieolytic effect of Catharnedulis more likely associated with more rapid onset of action of Cathinone, which agrees with its higherrnlipophilic character that facilitating entry into the CNS and a shorter duration of action, which agreesrnwith the rapid metabolism of Cathinone. The significant increased systolic and diastolic blood flowrnvelocities and the corresponding increase in resistance in superior mesenteric blood vessels in guinearnpigs enable us to conclude that khat chewing could decrease the volume of blood flow to therngastrointestinal system.rnKey words: Catha edulis Forsk, serum electrolyte, locomotors activity, anxiety like behavior, bloodrnflow velocity.