The intolercia the lactose even so reaches a considerable parcel of the world-wide population and Brazilian still she is unknown of many and little diagnosised. It is truth well that its symptoms easily are confused with diverse other problems, and only with a specific examination asked for by the doctor specialized in the digestive device it can be diagnosised. The intolerncia the lactose does not pass of a simple lack or reduction of the production of the enzyme lactase for the organism. This enzyme lactase has the function to break the lactose in two less complex parts and to liberate them sanguineous current it. With the lack of the enzyme lactase this does not happen, or happens very precariously, and all the consumed lactose goes to overload the intestine, and not to cover its natural way that would be for the sanguineous chain as glucose and galactose. One of the examinations most common is the ingestion of a certain amount of lactose and gradual checks in the amount of glucose in the blood. Through this test it is possible to know if the amount of sugar in the blood is of agreement with the amount of consumed lactose, and to diagnosis in this way a deficiency in the work them enzymes lactase, obviously for the lack or small number of these. After the diagnosis the carrying person of this intolerncia must take the necessary cares with the feeding for one better quality of life, in case that it wants to become free of the incovenientes as nauseas, gases, diarrias and all more than the intolerncia the lactose unhappyly provides. The lactose enters the common methods to prevent the problems of the intolerncia is the complete food withdrawal that possesss lactose in its composition and the ingestion of the enzyme lactase that it can be industrial or manipulated. It is good for knowing that the problem can have simple solutions and that the more people if to diagnosis intolerantes more the nourishing industry will go to aim the eyes to this parcel of the population and to launch products without the lactose, what already comes sufficiently lately happening.