Volatile liquid. The first product used in anesthesia (Campbell 1879). Today it is not used in many countries due to its dangerous nature (highly flammable) and side effects: mucosal irritability, delirium, postanesthetic vomiting (Campbell 1894), etc. Some of its derivatives such as dimethyl ether are still used as solvents and local anesthetics. Since the last update we have not found published data on its excretion in breast milk. Its short half-life (Butler 1964) would allow breastfeeding as soon as the mother is awake and is in a suitable condition. The popular custom in some cultures of applying creams containing ether on the abdomen for the purpose of slimming or firming during the postpartum period may be dangerous for the infant because of the anesthetic effects of the ether.