Few have done more than Furst, Stehle and colleagues1 to develop the concept of the conditional essentiality of glutamine in metabolic stress and to develop a means by which this amino acid can be practically added, as an alanine dipeptide, to parenteral feeds from which it has hitherto been lacking. The double blind randomised trial by Morlion et al assesses the clinical efficacy of such supplementation. It was conducted in 28 patients, well nourished as judged by weight for height, undergoing elective surgery for colorectal cancer. They were randomised to receive isonitrogenous (0.24 g nitrogen/kg/day) isoenergetic (29 kcal/kg/day) total parenteral nutrition over five days postoperatively such that one group received within its total nitrogen allocation 0.3 g/kg/day l-alanyl-l-glutamine, or about 20 g of the dipeptide—equivalent to 13.5 g glutamine. Mean (SEM) length of hospital stay in the controls was 21.7 (2.8) days and in the intervention group 15.5 (0.72) …