My Wife Eats, But Not Very Much, Soon After, But

my wife eats, but not very much, soon after, but mmost times while shes eating, she gets sick to her stomach and throws up everything she eats. Cannot hold anything down.been going on for some time. She takes doctor prescribed nexium, has had gall bladder surg, medicine for rheumatoid arthritis. digestive docs cannot find anything wrong, but she cannot eat without puking un-controllably to dump her stomach just after eating, please help.