Most babies throw up a little milk after feeds. Especially if the baby has not been burped well. This is because the air she had swallowed while feeding comes up. And, along with it a little of the milk she has had is also thrown out. This regurgitation is often described as vomiting.
After a feed, help your baby to expel this air by holding her against your shoulder with her head up and pat her back gently. This is called burping or breaking the wind.
Then put the baby on the bed with her right side down. This will help further expulsion of air.
A baby who vomits violently, too much, or too often, so much so that he becomes dehydrated or starts losing weight, needs urgent medical attention.
If your child is throwing up green vomit or if the vomit smells foul, like stool, she may have an obstruction in her guts. This will make her abdomen look swollen and she will fail to pass stools. Call the doctor immediately.