Allergy/cold/cough: Claritin is the antihistamine of choice. Diphenhydramine (Benadryl) is safe for moms of babies older than 1 month, though it can cause drowsiness in your infant and affect her ability to nurse. Stay away from diphenhydramine and other sedating antihistamines if your baby is premature or of low birth weight or uses an apnea monitor. For colds, the decongestant pseudoephedrine, the active ingredient in Sudafed, will not harm your infant, but new data suggests that it reduces milk production, says Hale. If you have a low milk supply, you may want to avoid it. For coughs, medicines that contain only guaifenesin - which is supposed to relieve chest congestion - are safe, but many experts consider them ineffective. Avoid dextromethorphan, another common anti-cough ingredient, as it has not been reviewed by researchers. And steer clear of multisymptom cold and allergy remedies, Sullivan advises; you might end up taking something you - and your baby - don't need.
Depression: Zoloft and Paxil, which regulate levels of serotonin, the "feel-good" brain chemical, are the safest choices among antidepressants. According to Hale, there are very low levels of these drugs in the milk of mothers who take them as well as in their babies' blood. Effexor and Wellbutrin are the next best bets. Avoid tricyclic antidepressants, such as Elavil and Tofranil.
Herbs: There is virtually no data on the transfer of herbs to a nursing infant, so it's best to avoid them - especially comfrey, kava-kava, chaparelle, feverfew, blue cohosh, and ephedra (ma huang), which have been shown to have adverse effects in adults.
Beth Howard is a freelance writer.