The authors undertook a preliminary study of two categories of patients to link morbidity and mortality to the nutritional condition of patients before and after surgery: the first group of patients were to be operated on for cancer; the second group was to act as a control group. For both groups, a study was made before and after surgery, of the nutritional condition of the patients and of progress, respectively. The findings revealed signs of de-nutrition in both groups and a distinct correlation between post-operation complications and the degree of de-nutrition. Hence, in the case of cancer, it is recommended some nutritional preparation before the operation.