For those who smoke, the best thing they can do for themselves and their baby is to quit. If this or smoking less is not possible, it is still better to breastfeed and keep breastfeeding. Smoking away from your baby and changing clothes to keep your baby away from the chemicals that smoking leaves behind are good practices.
An occasional drink is fine, but the American Academy of Pediatrics recommends waiting two hours or more before nursing. Drugs such as cocaine, heroin, marijuana, and PCP should not be used because they pose harmful consequences for infant development.