What can Coca Cola do to the interior organs?

Answer 1

Are you referring to Coca-Cola or Cocaine? The soda drink is very strong and can eat through battery acid, and has a lot of Caffeine, so Yes.
As for the drug, it constricts blood vessels, eats out the lining of your nose and is illegal, so Yes. I've been drinking diet Coca-Cola for years and have suffered no ill effects from it. Caffeine in itself is not harmful. The best thing to used for removing battery acid deposits is a mixture of water and baking soda. Coca-Cola will remove tar from the paint on a car though.
I agree with the above on the drug effects.

Answer 2

my dad has been drinking cocacola for 18years he used to drink 3 letres a day to him self we think the cocacola in rotting his insides can that be true if so what is the ingredient that could be doing that?