Toddler's vomit for several reasons and most often it's nothing to worry about. Vomiting is yet another common occurrence in toddlerhood. Even so, most parents won't rest easy until they know what caused it, and rightly so.
Quite often you'll find that your toddler threw up once and that was the end of it. This merely implies that he ate a wee bit too much of his last meal. In this case, you don't need to do much, except ensure he doesn't over-eat his next meal. However, there could be several other causes of vomiting in toddlers, especially if they throw up more than once.
A viral or bacterial infection like stomach flu is the most common cause. It could be diarrhea as well, which could be caused by viruses and bacteria lining the stomach and intestines. These infections also cause loss of appetite, stomach ache and sometimes even fever. However, in these cases vomiting ceases in a day or two.
It could be that your child doesn't respond well to motion. This happens because your toddler cannot make a connection with what he sees and what he senses. Therefore, being in motion, like in a car, or riding a Ferris wheel can trigger off nausea. If this is a toddler vomiting cause then it could be difficult especially if the child has to take a car or bus trip on a daily basis.
Toddlers are known to throw tantrums. It is likely that one such tantrum, especially one where your toddler is crying non-stop for a very long period of time, he could cough to catch breath and the reflex of catching his breath could make him vomit. This can unnerve you but it's not going to cause health issues for your toddler.
Toddlers are perennially curious and even though they are done teething they are still inclined to put things in their mouth. So, it is sometimes possible that your toddler has swallowed something toxic, or had a medicine or plant which could trigger off food poisoning. Of course, he could also get food poisoning from consuming contaminated food or water.
Any other infection, sometimes even a regular flu, can cause vomiting. In fact, an ear infection, or urinary infection can cause your toddler to throw up. Of course, vomiting is also an early symptom of various serious diseases like appendicitis, pneumonia, jaundice, meningitis and various other stomach and intestine related infections.
It's hard for a parent to know the exact cause or causes of toddler vomiting. If it happens only once you can ignore it, however, if there is repeated vomiting, it's best to avoid guessing games and consult a doctor about it.