During lactation, the consumption of ethanol is discussed controversially. After women drink alcoholic beverages, ethanol can be found in breastmilk with a time lag. To abstain from ethanol, but not from the taste of alcoholic beverages, in particular, non-alcoholic beer has become popular in recent years. According to regulations in the United States and most European countries, these "alcohol-free" beverages may still contain ethanol up to 1.2% by volume. To determine how much of this ethanol may reach the breastfed child, a drinking experiment with non-alcoholic beer was performed.Fifteen healthy breastfeeding women participated in the study. After at least 5 days of abstinence from ethanol and the donation of a void breastmilk sample, they were asked to drink 1.5 L of non-alcoholic beer within 1 hour. Breastmilk samples were collected using electronic breast pumps immediately after the end of drinking as well as 1 and 3 hours later. The milk was analyzed for ethanol by headspace-gas chromatography-flame ionization detection using a fully validated method.In two women, trace amounts of ethanol (up to 0.0021 g/L) were found in the samples gained immediately after the drinking period. In the other samples ethanol could not be detected (limit of detection=0.0006 g/L).The mother's consumption of non-alcoholic beer is likely innocuous for the breastfed infant.