Well, he has had a kind of clean cold (basically running in the inside), he has been having a wet chesty cough during the night and this morning he vomited (sorry to be graphic) something that had the colour of the antifreezing product we use in our cars (but more yellow than green). I suppose its phlegm combined with bilis. He seems fine otherwise so the question is... what should I feed him (or have to avoid) in order not to upset his stomach further?