My son has been throwing up randomly over the past 4 days. For example, he threw up on Saturday morning, was fine all day Sunday, threw up at midnight on Sunday, went to sleep right after, played all day today ate normally and did fine until around 7:30 pm and then got sick again. After getting cleaned up, he has asked for food, and is playing like nothing happened. He does not, nor has he had a fever . Could this be related to sinus drainage? Could it be stress , as he is a foster child and I had just told him before bed on Sunday night that he had a visit on Monday with his bio-mom and tonight when he got sick, he had just become upset for accidentally bumping heads with his foster dad?