Hi ,I Have A 6 Year Old Girl,she Gets Sessiona

Hi ,I have a 6 year old girl,she gets sessiona of sudden vomitting out pf the blue at night,then the vomitting lasts till the next day morning or sometime till evening..after one session of this vomitting she wil be fine and if nothing triggers may be for months she don't vomit..most of the time what triggers her vomitting is chocolates and ghee..too much of chocolate intake sometime triggers it...why could be this happening...there is no medi which I give her now,just treat her by keeping her hydrated..my grandfather was in medical field with the Indian army,he told me to give liv52,since she is a picky eater...but I have doubt about this as well,.is it of any good?...Thank you.