My nephew just died - He was not drunk and was not using illegal drugs. He has a hx of percocet abuse but none recently. He did take some xanax prn along with his bipolar medications. When he was found, he was having labored breathing and shortly began to foam at the mouth. He died shortly after this foaming began. He had abdominal pain and vomiting for approx 3 days prior. What are the possible causes for his foaming of the mouth and death....any ideas?