SummaryOne of the essential requisites of the treatment of catabolism inducing diseases is the maintenance of an adequate nutritional status. When this cannot be achieved by the usual means (normal or forcible feeding), it is necessary to have recourse to parenteral nutrition. An adequate supply of nitrogen, ions, water and calories can either totally replace or complete the feeding and restore a satisfactory nutritional equilibrium, even in cases of cachectic diseases.The nutritional program must comply with the following criteria:1. The caloric needs of the patient, which can be considerable, have to be met: an average of 2,500 to 4,000 calories per day including 12 to 20 gm nitrogen.2. At least 10% of this amount must be given as carbohydrates.3. The nitrogen is supplied by protein hydrolysate or synthetic amino-acid perfusions. The optimal proportions between all the amino-acids (essentials and non essentials) must be accurately kept to. In order to achieve the best protein anabolism, 150 to 300 calories should be given per gm of nitrogen perfused. This may be achieved by associating carbohydrates with the protein perfusions and by simultaneous perfusion of a lipid emulsion or of a concentrated glucose preparation.4. Two to three gm lipids per kilo per day should be administered. Some lipid emulsions are well tolerated (soya oil emulsified by egg yolk phosphatides) and make a considerable caloric contribution possible.5. The needs of water and ions have to be adapted to each individual case. Vitamins are an essential part of prolonged parenteral nutrition.Parenteral nutrition is frequently indicated. It is practically inocuous. However, care is needed when administering lipid emulsions to hepatic patients.It is to be noted that the high caloric lipid emulsions or protein containing solutions at present available in Belgium are not those generally indicated.The introduction into our country of soya oil emulsions as well as new protein solutions better balanced in the relative proportions of the different amino-acids as well as in their nitrogen-caloric ratio will be a notable step forward in what has been hitherto a neglected aspect of the treatment: the maintenance of the patient in optimal nutritional status.