My 14 year old son recently had a stomach infection and was treated with antibiotics. The diarhorrea continued intermittently so the doctor carried out tests which revealed nothing, so he is avoiding milk and chocolate. Today he was sent home from school with dizziness, a headache and cramp but no diahorrea. He had tomato sauce in his meal last night, but otherwise nothing else we know to bring on diahorrea (tomato has not proved to do that yet.)