Hi. Thanks for your query. Noted the history and understood the concerns. Vomiting and diarrhea in a patient with known mesenteric lymphadenopathy indicate severe inflammation in the lymph nodes as primary cause or secondary cause due to appendicitis, diverticulitis and so on. Hence I would advise you friend the following: Clinical evaluation, examination by a Doctor, preferably a General Surgeon. CT scan of the whole abdomen to get an exact cause. A course of an antibiotic, metronidazole and probiotics may help to have cure. If the primary cause is found he will be treated specifically by surgery or so.