Caffeine is a central nervous system stimulator and the most widely used over the counter medications in the world. It is belongs to the class of molecules known as xanthines 1, Caffeine is found in tea, coffee, mate, guarana paste and kola nuts which are used to flavor soft drink colas and Cacao pods, which are used to make chocolate products.2There is also synthetic (man-made) caffeine, which is added to some medicines, foods, and drinks. For example, some pain relievers, cold medicines, and over the counter medicines for alertness contain synthetic caffeine. So do energy drinks.Caffeine has many effects on your body’s metabolism. It Stimulates your central nervous system, which can make you feel more awake and give you a boost of energy also diuretic, meaning that it helps your body get rid of extra salt and water by urinating more increase the release of acid in your stomach, sometimes leading to an upset stomach, and increases your blood pressure.3Pharmacological Activity and Adverse Effects shows that at low dose 50-250mg Caffeine it will increase mental alertness, decrease drowsiness Lessen fatigue, however at Larger doses 250-600 mg it will cause Caffeine Irritability, restlessness, tremor, insomnia, headache, palpitations and hyperesthesia GIT upset. While more then 1000 mg Overt excitement, delirium and clonic seizures4Caffeine conception has a significant effect on human behaviors which is important in University Students and their Grade Point Average for example it participate in low arousal situation because it increases alertness and reduce fatigue (e.g. working at night)(5). Since the caffeine has positive and negative effects on performance, one of the major role that improve the performance on tasks, concentration, energy and memory in contrast with high caffeine intake has shown that leads to increase anxiety and impair sleep, therefore caffeine withdrawal leads headache, drowsiness, irritability, nausea and difficulty concentrating that is relatively explaining changes in GPA (6). There is also 2 some evidence that fine motor control may be impaired as a function of the increase in anxiety and depression.The study will specifically focus on the effect of caffeine consumption on Grade Point Average and psychological behaviors among female preclinical medical students in Riyadh, Saudi Arabia.