The best evidence we have suggests that there is no safe amount of alcohol from the standpoint of heart disease[1]. The data supporting the safety (or even benefit) of a small amount of alcohol came from observational studies, which are often heavily confounded. This study used Mendelian randomization (MR) to get around that limitation. MR can be confounded by pleiotropy, but this study (which suggests harm from alcohol intake) is still higher quality evidence than the observational studies done previously.