Hi and thanks for the query,
It shall be important consulting a pediatrician
for a proper evaluation. Considering the possibility of a food intolerance
to a particular food is an important consideration. The characteristics of the diarrhoea
are important. Does he have diarrheoa at particular moments of the year, when he visits particular areas, associated with given foods, accompanied by fever
or not, is he growing normally or something? These are all issues that shall be considered in the evaluation. However, as you wait to see the pediatrician, I suggest you ensure that he eats clean foods, take care and monitor whether he is going to be having diarrhoeal episodes when he eats certain foods and also the characteristics of the diarrheoa(watery, bulky, accompanied with blood etc).
Thanks and hope this helps,