Super thin baby, constantly vomiting....HELP!? There is a woman I know that is taking care of her grandbaby.  Her son works during the day and can't take care of the baby at night.  The baby's mom is a drug addict, she dropped the baby off two weeks ago and hasn't been back.  The baby is only about a month and a half old, but STILL looks like a premie.  According to the grandmother the baby was given a clean bill of health when he was born, but there is something not right.  The baby continues to vomit (I don't mean spit up....but vomit, with the smell of adult vomit!!).  He doesn't look like he is gaining any weight and even his cry sounds distant.  He looks like he might be in pain.  I know that the grandmother is taking care of him to the best of her ability.  I have never seen a baby like this before and think that he may have a serious condition.  I don't want to call social services since the baby isn't being mistreated.  I need suggestions

Summarized question: What causes vomiting in a newborn baby?