Is drinking more coffee effect the health

Anything if gone beyond a limit will cause problems. Thats true with everything in the world, So it will apply to coffee also.

Having too much of anything(even vitamins) can have bad side effects. People who drink too much coffee will be addicted to it. They'll have dark stains on their teeth, their breath smells foul and they tend to be hyperactive. It also makes your nerves more intense. Everything should be taken in moderation. Like, do you know in men when you take too much vitamin E you'll develop boobs? That's true.