Hi and welcome to Healthcare magic.Thank you for the query.
renal and liver failure
usually cause refracter vomiting
and this is hardly teratable but there are certain medicines which can help so consult your doctor about it. He should also change dietary habbits,eat easier food more frequently but in smaller meals. also he should do frequent liver and kindey functional tests because high urea and creatinin elevels can cause excessive vomiting and nausea
Wish you good health. Regards