Republished from 2010 with updated links
Almost all babies are going to spit up from time to time. Some more than others. My firstborn seemed to coat every surface of our house in barely digested breastmilk, from the back of the rocking chair to the changing table to the staircase (a particular favorite). He was a "happy spitter" and would act like nothing had happened, while he was covered from chin to crotch in slime. Luckily, in time, he grew and his esophagus grew with him and the distance between the top of his stomach and the back of his throat got longer...and the food stayed put more often.
Not all babies are "happy spitters" they scream after they spit up and, in time, they may start to refuse to eat because they associate eating with what happens afterward. If you suspect your baby has symptoms of reflux, also known as GER (gastroesophageal reflux), it is important to work closely with your health care provider and a lactation consultant to resolve the issue. Breastmilk is the best food for babies with GER because it is easily digestible and it has natural antacid properties. Keeping baby as upright as possible throughout the day will keep stomach acid from creeping up into the esophagus. Many parents find babywearing useful to keep babies comfortable and close for smaller frequent feedings (rather than large feedings that could cause more strain on stomach/esophagus). Using an upright breastfeeding position (anything where baby's bum is significantly below baby's shoulders) may also help make baby more comfortable, especially if mom has a strong let-down or faster flow. Some babies with GER can be helped with breastfeeding management and upright positioning alone, others may also need to incorporate medication prescribed by the baby's health care provider. For babies who need it medication can be a God-send for parents who have tried everything else, but it is a long-term commitment to giving baby a daily prescription.