As much as I love Drunk History, I'm afraid it's a story telling by drunk people. It's slightly worse than getting your history from Eddie Izzard. The most it's good for is finding a story or person you didn't know about before and going to get a book on the topic.

It is absolutely hilarious though.

EDIT: Here is an interview with Derek Waters on how Drunk History is made. Count the number of times "history" turns up in his answers.