Healthier: Oatmeal or Oat Bran?

I want to buy hot cereal to have in the morning. My colon is sluggish so should I buy oat bran? Is it healthier than oatmeal? Or should I buy oatmeal and stir in some bran? I am just confused. Does oatmeal have more health benefits than oat bran or vice versa? Everyone talks about how healthy it is to have oatmeal in the morning but no one mentions oat bran. Help me out here!