at what age can infants have cereal in there milk?

They can have cereal around the age of 6 months. If they are showing signs of consent hunger (and able to have control over head movement and able to sit with support) they can have some as early as 4 months. You should start them on plain rice cereal as it's easier for them to digest then moving to barley/oats then mixed and so on. Another thing that's not advised to do is putting cereal into thier bottles. Feed them thier cereal from bowl and spoon, you can water down the cereal to make it as runny as you want.