Objective To assess whether application of cocoa butter lotion reduces the development of striae gravidarum (SG).Design Multicentre, double-blind, randomised and placebocontrolled trial.Setting Beirut and Tripoli, Lebanon.Population Nulliparous women presenting for prenatal care.Methods Nulliparous women presenting in the first trimester were randomly assigned to receive a lotion containing cocoa butter or a placebo lotion. Women were instructed to apply the assigned lotion daily until delivery.Main outcome measure The development of striae over the abdomen, breasts and thighs postpartum.Results Of 210 women enrolled, 175 (83%) completed the study. Ninety-one women received the study lotion and 84 received the placebo. There was no difference in the development of SG (45.1% versus 48.8%; P = 0.730) or the severity of SG between cases and controls. The results did not change when presence of stretch marks at enrolment or compliance with the regimen were taken into account.Conclusion Topical application of a lotion containing cocoa butter does not appear to reduce the likelihood of developing striae gravidarum.