No! It's true that if you smoke, nicotine and other garbage will end up in your milk and may cause harm to your baby, such as nausea, vomiting, abdominal cramps and diarrhea. (Secondhand smoke isn't good for your child, either, so if you're going to smoke, make sure you do it when you're not around her.) Also, do not smoke two hours prior to breastfeeding, if possible. But the benefits of breastfeeding--higher IQ and reduced risk of ear infections, diarrhea and some childhood cancers, to name just a few--far outweigh the negative aspects of smoking while nursing.