Does drinking beer make radiation for colon cancer less effective?

No: Radiation works on an atomic level through ionization. Free radicals are created and these ultimately damage a cells dna disrupting their survival. Beer has nothing in it to stop that process. Doctors and nurses however tell people to stop drinking so the side effects are not increased. As long as their is no diarrhea and one drinks one or two beers there should be no harm. And not daily.

Unknown: I am not aware of any study of radiation effectiveness and beer consumption. I do not believe beer in moderation would have an effect.