My toddlers breath smells like sick, but he is behaving and eating normally. is there anything wrong with him or is this normal?

Ok: toddlers typically have sweet breath. Bad breath in this age is unusual. I worry about things like dental disease, tonsils or sinus disease. Kids don't have much in the way of sinuses but they do have some. Ive even had patients with bad breath who had a bead and a bean stuck in the nose unknown to the parent. Chronic colds and dental disease are the most common reasons in my experience.