Hi, Thanks for writing in. It is possible that he is having rapid cycling vomiting syndrome. Cyclic vomiting syndrome is characterized by episodes of severe vomiting that have no apparent cause. Episodes can last for hours or days and alternate with relatively symptom-free periods of time. Each episode is similar to previous ones, meaning that episodes tend to start at the same time of day, last the same length of time and occur with the same symptoms and level of intensity. It will help to consult a gastroenterologist and get examined clinically. Treatment involves managing symptoms and lifestyle changes to help prevent the events that can trigger vomiting episodes. Medications are to be given at the time when he starts feeling nausea and the vomiting episodes might be controlled.