Lack of information and misinformation often lead to physicians advising mothers to discontinue breastfeeding because of medication use. Also, many mothers do not adhere to their prescriptions or quit breastfeeding because of medication use. Although in both cases this cessation of breastfeeding is probably based on concern for the infant's safety, the physician may also be influenced by expediency and fear of litigation. The safest course for physicians who are treating nursing mothers is to consult reliable sources before advising discontinuation of breastfeeding. Overwhelming evidence has shown that breastfeeding is the most healthful form of nutrition for babies and should therefore be encouraged by physicians. Physicians should take the following approach to maximize safe maternal medication use for both the mother and the breastfed infant: 1. Determine if medication is necessary. 2. Choose the safest drug available, that is, one that; is safe when administered directly to infants, has a low milk:plasma ratio, has a short half-life, has a high molecular weight, has high protein binding in maternal serum, is ionized in maternal plasma, is less lipophilic. 3. Consultation with the infant's pediatrician is encouraged. 4. Advise the mother to take the medication just after she has breastfed the infant or just before the infant's longest sleep period. 5. If there is a possibility that a drug may risk the health of the infant, arrange for the monitoring of serum drug levels in the infant. Emergency physicians are often faced with the daunting task of treating a large variety of high-acuity patients, including patients who happen to be pregnant or nursing mothers. Priority, of course, needs to be given to life-saving treatment. When physicians are treating pregnant or breastfeeding patients, they need to use reliable resources to evaluate the risks and benefits of the medication for the mother and the infant. Most medications should have no effect on milk supply or on infant well-being. In most cases, treatment plans for patients should include encouragement from the emergency physician that he or she has researched the chosen medicine and that breastfeeding may safely continue.