That only applies to creatures with the alignment subtype. Such as, a demon (Evil, Chaotic) has damage reduction Good, and its weapons are considered evil and chaotic, to overcome the DR most good aligned creatures would have.Scharlata said:Remember: If you got DR, you can overcome the DR of certain creatures, IIRC
And many monsters that have DR magic may say that their natural weapons count as magic for overcoming DR.
BUT
Just because you have it doesn't mean you can get through other's DR. An iron golem has DR adamantine, but it does not have weapons that count as adamantine.