Khat (Catha edulis forsk; family: Celastraceae) is a plant habitually chewed by several millions of people in Yemen and southern east areas of Africa for its pleasant stimulant effect on physical activity, consciousness, motor and mental functions as well as its anti-fatigue action. This study was aimed to investigate the implication of chronic khat-habituation on levels of the main inhibitory neurotransmitter, GABA, in relevant areas of brain namely cerebral cortex, midbrain and hindbrain in an animal model. Eighteen mice (20-30gm) were used in this study; they were grouped into control, Khat-habituated, and khat-withdrawal. Khat-habituation was induced by providing khat (2g/kg) with food for two months. Khat-withdrawal was induced by cessation of khat-containing food for 14 days. The GABA levels in brain areas were determined quantitatively using chromatographic and calorimetric method. Khat-habituated animals showed significant decrease in GABA contents in tested brain areas. Khat-withdrawal for 14 days reversed effects caused normalization for GABA levels in brain. Chronic khat-habituation has transient deleterious effect on the levels of GABA in the brain which may reinforce the development and spread of epileptic discharges, this effect may be reversed after its cessation.