Vomiting Problems

Hi,

my girlfriend has a problem where once she gets a sore throat her reaction is typically followed by a constant bout of vomiting (she seems to vomit constanly every 1/2 hr - 1hr) that seems endless and it can take her up to a full week to recover. She has undergone numerous tests to see what causes her sore throats (sometimes they are from a cold or flu, and at other times there are unknown causes)however they have found nothing. What I am concerned about more is not her sore throats but this reaction she gets from them of constant vomiting which sometimes can only be stopped by an injection or a pill which her doctor has prescribed her. It can get really bad and she has been in hospital at one stage. They have done an endoscopy (i think thats how you say it) where they put a tube and camera down her throat to see if she has any infections or ulcers in her stomach or throat but again have found nothing and it seeems her doctor and specialist cant pin point the problem and have even admitted they dont know what causes the problem or why she reacts like this. Some people say its her diet and that she cant eat this and that but she does not eat junk all the time and usually eats good home cooked meals. Can some one please help, any suggestions or ideas or further stepds to take? I am really concerned for her well being.

Joe