Baby has had another reaction to rice porridge. Been vomitting yellow bile, when must I worry?

Possible Allergy. Without knowing the age of the baby it is hard to say for sure. It could be a food intolerance. They only way to know for sure is to stop the rice porridge and see if the vomiting goes away. If the try the rice again and the baby vomits than the baby has an intolerance to the rice porridge and it is best to try another source of nutrition. If the vomiting persists then take the baby to the doc.