Oral nutritional supplements (ONS) are often used to treat malnutrition in COPD, but the latest Cochrane review in COPD concluded that nutrition support, mainly involving ONS, did not improve anthropometry and other functional outcomes.1 The latest NICE guidelines for the management of COPD recommend the use of ONS but state it is based on grade D evidence2 despite previous reviews suggesting otherwise.3 This review aimed to clarify the evidence base for ONS use in COPD. A systematic review identified 11 randomised controlled trials using ONS vs control (189 vs 185). Meta-analysis was performed of nutritional intake, weight, mid-arm muscle circumference (MAMC) and handgrip strength (HGS) (Comprehensive Meta-analysis v2). Quality of life, exercise capacity and respiratory outcomes were also examined. In contrast to previous Cochrane reviews, examining only data at the end of intervention,1 this review examined the changes induced by ONS. Significantly improved energy intake was reported in six out of seven studies of which four were meta-analysable (+262 SE 104 kcal/d, p=0.012, random effect model, four RCT). Meta-analysis found ONS significantly improved body weight (+1.85 kg SE 0.25 kg, p<0.001 (malnourished) and +1.31 kg SE 0.34 kg, p<0.001 (nourished), 11 studies) and had a tendency to improve MAMC (+0.21 kg SE 0.19 kg, p=0.277, fixed effect model; I2=0; 2 studies). Improved HGS was found in three of four studies, two significant in their own right with meta-analysis favouring ONS (+2.14 kg SE 1.1 kg, p=0.054, random effect model (+8.3% improvement)). No improvements were reported in FEV1 (eight studies) however, respiratory muscle strength appeared more responsive to ONS with PI max improved in three out of five studies (NS), PE max significantly improved in two out of four studies and sternomastoid strength significantly improved in one study. Exercise tolerance (six out of seven studies), dyspnoea and general well-being (three out of five studies) and quality of life (two out of two studies) were significantly improved with ONS although meta-analysis of these outcomes was not possible. ONS result in significant improvements in nutritional intake and body weight and a tendency for improvements in several functional outcomes. This would support an increased level of evidence for ONS in the NICE COPD guidelines.