Overweight and obesity are recognised as responsible for an increase in vascular risk and in excess mortality due to cardio-vascular diseases. This is especially true in presence of increased visceral (central) fat distribution, a key factor for insulin-resistance, the main component of the metabolic syndrome X. Cardio-vascular risk in overweight and obese subjects appears strongly correlated with the common risk factors, more frequently present in these patients: type 2 diabetes, hypertension, lipid abnormalities. Weight reduction improves all risk factors and decreases the patient's global vascular risk. The improvement in the various risk factors is significant with a moderate weight loss (10% of the initial weight). Weight reduction should been obtained always with nutritional-hygienic means (physical activity, weight-reducing diet...) maintained for several months. Only when these approaches appear to be insufficient, the need for an associated pharmacological treatment has to be considered. Amongst the weight-reducing drugs currently available or close to be, orlistat has demonstrated its interest in the glycemic control of type 2 diabetic patients, and its favourable effect in hypertensive patients. Available clinical studies have clearly shown the more marked effect of orlistat in comparison to placebo in reducing the various risk factors. So far, few studies have been conducted to assess the effects of the specific drug therapy on the control of metabolic abnormalities and risk factors in overweight or obese patients, except in type 2 diabetic patients for whom, most of the oral anti-diabetic agents have been tested in overweight or obese diabetic population.