Obesity is a complex multifactor disease characterized by excessive accumulation of adipose tissue that may impair health. The prevalence of obesity is rapidly reaching epidemic properties in developed nations. Monosodium glutamate, the sodium salt of glutamic acid is a food additive used as a flavoring agent for enhancing taste, may be associated with increased risk of overweight in humans This work was planned in order to assess the effect of obesity induced by high fat diet and monosodium glutamate (MSG) on platelet aggregation.