<s>[INST] Every month or so my 13 year old son gets major diarrhea and vomits once. He does not run a fever during this time. He also complains of having a rotten egg taste in his mouth or of burping rotten egg taste. What is this and why does it keep recurring? [/INST] dear userabout your question i would like to tell you that recurrent diarrhea has some causes in this age of your son.......allergy to food cause the intestinal movement to increase rapidly so causing diarrhea and vomiting.......so you should notice if there is food that if he eat symptoms increase to avoid that food  second if your son had intestinal infection of the past or had severe gastroenterities that may cause damage of intestinal epithelium and so maldigestion and recurrent diarrhe occur and it will need some time to improve gradually as it is self limitedif your son eat unhealthy food or fatty food or spicy food that may cause these symptomsalso you should do stool culture for him and widal test to detect if there is salmonnela infection causing typhoid or another intestinal infectionas the intestinal infection viral or bacterial should be managed to end of this problemhope that helps youi wish you and your son happy life </s>