Starting your baby on solids usually starts with single-grain cereals like rice. Soon you will gradually give your baby other foods. Introduce one new food at a time, and wait at least 2 to 3 days before starting another. You will want to watch for any allergic reactions such as diarrhea, rash, or vomiting after each new food is introduced. Stop using the newly introduced food and speak with your Loveland family medicine doctor if this happens.