Back ground of the study:Estimated 20 million peoples chew khat in the world. Khat chewingrnhabit in Ethiopia and other countries is a socio-medical problem. Khatcan affect different bodyrnsystems like cardiovascular system, central nervous system, and other systems.There are a fewrnnumbers of studies that concerned on the effect of khat on human physiology,because most ofrnresearchers concentrate on the pharmacokinetics of khat. These studies revealed on the acuterneffect of Catha edulis(khat) on electromyography, arterial blood pressure, heart rate and onrnelectrocardiography.rnMaterials and methods:We studied the effect of khaton electromyography, arterial bloodrnpressure, heart rate, and electrocardiography in humans. Biopac MP 35was used to measure thernabove dependent variables. Physiological parameterchanges were studied before and after khatrnchewing. Allbaseline measurements were taken before chewing khat. Participants were providedrnwith 100gm of pure palatable khat leaf and bottled water (soda). Post measurements werernconducted 2 and half hrs. after they started chewing. They were abstained from taking any otherrnstimulant during the study time. The EMG measurements taken were maximum force, meanrnforce, Raw EMG, Integrated EMG and Fatigue time. These parameters were measured byusingrnhand dynamometer with their dominant hand. Systolic and Diastolic blood pressure,heart raternand ECG were also measured by using Biopac.rnResults: The maximum force generated by dominant arm skeletal muscles by study participantsrnhad shown significant increase after chewing khat.Its mean value was 30.80 Â±1.3 before chewingrnand 34.38 Â±1.30 kg after chewing(P