Abstract: We identified 18 eligible primary publications (21 trial reports). A total of 3089 infants participated in the trials. The risk of bias varied with lack of clarity on methods to conceal allocation in half of the trials and lack of blinding of caregivers or investigators in all of the trials being the main potential sources of bias. Eight trials (2086 infants) examined the effect of topical ointments or creams. Most participants were very preterm infants cared for in health-care facilities in high-income countries. Meta-analyses did not show evidence of a difference in the incidence of invasive infection (typical risk ratio (RR) 1.13, 95% confidence interval (CI) 0.97 to 1.31; low quality evidence) or mortality (typical RR 0.87, 95% CI 0.75 to 1.03; low quality evidence). Eleven trials (1184 infants) assessed the effect of plant or vegetable oils. Nine of these trials were undertaken in low- or middle-income countries and all were based in health-care facilities rather than home or community settings. Meta-analyses did not show evidence of a difference in the incidence of invasive infection (typical RR 0.71, 95% CI 0.51 to 1.01; low quality evidence) or mortality (typical RR 0.94, 95% CI 0.81 to 1.08; moderate quality evidence). Infants massaged with vegetable oil had a higher rate of weight gain (about 2.55 g/kg/day; 95% CI 1.76 to 3.34), linear growth (about 1.22 mm/week; 95% CI 1.01 to 1.44), and head growth (about 0.45 mm/week; 95% CI 0.19 to 0.70). These meta-analyses contained substantial heterogeneity. The available data do not provide evidence that the use of emollient therapy prevents invasive infection or death in preterm infants in high-, middle- or low-income settings. Some evidence of an effect of topical vegetable oils on neonatal growth exists but this should be interpreted with caution because lack of blinding may have introduced caregiver or assessment biases. Since these interventions are low cost, readily accessible, and generally acceptable, further randomised controlled trials, particularly in both community- and health care facility-based settings in low-income countries, may be justified.

Plain-language summary: Study characteristics: Our search (August 2015) identified 21 eligible trial reports (in 18 primary publications). In total, 3089 infants participated. Eight trials (2086 infants) examined the effect of topical ointments or creams. Most participants were very preterm infants cared for in health-care facilities in high-income countries. Eleven trials (1184 infants) assessed the effect of sunflower, sunflower seed, and other vegetable oils. Nine of these trials were undertaken in low- or middle-income countries and all were based in health-care facilities rather than home or community settings. Results: Analyses of these trial data provided low quality evidence and did not show that emollients prevent infection or death in preterm infants. Conclusions: These analyses do not provide evidence that the use of emollient therapy prevents invasive infection or death in preterm infants in high-, middle- or low-income countries. Since these interventions are low cost, readily accessible and generally acceptable, further randomised controlled trials, particularly in both community- and health care facility-based settings in low-income countries, may be justified.