Hi and thanks for sharing your concern with us on HCM. I am very concerned that your son is having intestinal obstruction. The vomit that you mentioned sounds as though it contains fecal matter (poop) in it. Vomit with poop in it suggests that there is an obstruction beyond the ileum (final part of the small intestine). An intestinal obstruction is a MEDICAL EMERGENCY and throwing up poop is a sure sign that you need to get your son to the nearest hospital. Causes of intestinal obstruction in children include cecal volvulus (the colon gets twisted, causing obstruction) or intussusception (intestine telescopes into itself). These conditions cannot go away on their own, be treated with OTC medicine or treated by a clinic doctor. I know this sounds scary but you need to be calm and act fast. Get your boy to a hospital where imaging studies using x rays, contrast or even ultrasound can be quickly done to diagnose the problem. Blood work will also need to be done to establish your boy s condition. Treatment will be promptly carried out depending on the situation. I hope you can quickly get your boy to treatment. Good luck and take care Dr Shabnam