Yes, if the doctor recommended adding rice cereal to breastmilk or formula
as a thickener to decrease reflux
Otherwise, babies under 4 months of age do not eat baby food. They only drink breastmilk and/or formula. Baby food is started at 6 months. Some parents try giving rice cereal at 4-5 months, but that usually is not necessary. It's best to wait until 6 months.