Nutritional assessment variables were measured weekly in 10 young women with severe anorexia nervosa during treatment with total parenteral nutrition (TPN) for a 5 week period. Before the start of treatment the patients had lost 25-53% of their habitual weight, triceps skin fold (TSF) and arm muscle circumference (AMC) measurements were below the 5th percentile and all were anergic in the delayed hypersensitivity (DH) response. Plasma protein levels were normal except in fibronectin and prealbumin where levels below the reference interval was found in five patients. During TPN the body weight increased most likely due to rehydration and increase in lean body mass. Significant increases were seen in body weight weekly, but in TSF and AMC only after 4 and 3 weeks respectively. TSF and AMC were still below or at the 5th percentile after 5 weeks of TPN. DH response as well as fibronectin and prealbumin levels normalised in all patients. Despite only partial recovery in body cell mass the clinical picture had changed markedly so that the patients now were amenable to psychotherapy and had an adequate intake of food orally, enabling further nutritional therapy to be completed without parenteral support.