Appropriate nutrition to patients in the intensive care unit (ICU) is an important modality of treatment. Lack of knowledge and overenthusiasm have resulted in nutrition-related complications, which are unacceptable. In the literature, there have been several reports indicating that all the beneficial effects of nutrition may be outweighed by the complications. Although there is overwhelming evidence that starvation or semistarvation eventually leads to death, this has not been accepted as a fact in ICU patients. There are no prospective randomized controlled clinical trials on this point because such a trial would not be considered ethically acceptable. Even so, hypocaloric nutrition in long-stay ICU patients is probably fairly common. Glutamine is an amino acid, which is a natural constituent of conventional food. However, due to instability in aqueous solution, it has not been a part of intravenous nutrition. In the literature, there is massive documentation concerning the central role of glutamine in amino acid and carbohydrate metabolism. In many experimental settings, such as cell cultures, there is no cell-growth unless the medium contains a certain concentration of glutamine. Concerning the clinical advantage of glutamine-containing nutrition versus nutrition that does not contain glutamine for ICU patients, the literature is unfortunately not very extensive. There is only one prospective controlled randomized trial. 1 Although it represents high-quality work, there are some limitations, such as a comparatively small number of patients and the study being executed in one center. In addition, many studies have focused on various aspects of morbidity as the endpoint. The strength of the documentation is the demonstration of positive effects or, in some cases, no significant effect, but so far there has been no study showing a negative effect. Nevertheless, taken together, the available documentation for glutamine-supplemented nutrition is the best documentation of a specific nutrient that exists today. In this and the previous issues of Nutrition, there are two more articles containing evidence that glutamine has a beneficial effect on ICU-associated infections. The study by Conejero et al. in the present issue is a multicenter study on the use of enteral glutamine demonstrating a reduced frequency of ICU infections. The study shows some similarities with a study containing only trauma patients from one center. 2 However, this study shows a similar result in a more mixed patient group, with patients from several centers receiving enteral nutrition support. The design is similar, with an adequate supply of enteral nutrition and an adequate amount of glutamine. The second article is a follow-up of the study by Griffiths et al. 3 It is a post hoc analysis of bacteriologic and mycologic agents found in cultures from ICU patients. It showed that glutamine-treated patients had fewer serious infections and less frequent hematogenic spread of Candida albicans. This information adds to our understanding of the beneficial effects of glutamine. Today we try to use evidence-based medicine to guide our decision making, which means using the best available information. The results published in this issue of Nutrition add evidence to the advantage of using glutamine-supplemented nutrition in ICU patients, but we are all waiting for a prospective randomized controlled trial with mortality as the endpoint in ICU patients. If one can anticipate a reduction in ICU mortality from, say, 30% to 25%, 2500 ICU patients are needed. Because nutrition is a problem primarily for long-stay patients in the ICU, this will necessitate an international multicenter study to recruit a sufficient number of patients. Meanwhile, we have to rely on existing information from a number of studies representing circumstantial evidence and, perhaps equally important, the absence of reports of severe complications.