Can my 4-month-old start cereal?

Usually. A baby is ready when he can hold his head up enough to eat from a spoon. Use a spoon to feed your baby cereal, not a bottle or infant feeder. Sitting up while eating helps your baby learn good eating habits. When you start cereal, start with rice cereal mixed with breast milk or formula. You may want to start with a thin mix of cereal and thicken it gradually.