I read about a study that says coffee can reduce the chance of getting
Parkinson.

Caffeine makes you perform better on tests. It does not stay in the
brain long.

Of course, everyone knows too much caffeine will give you the jitters.

There is no link between caffeine and cancer and osteoporosis.

There is evidence that coffee protects against gallstones.

I also read a long time ago about how the chemistry of caffeine works in
the brain. It doesn't really keep you awake--it represses the production
of chemicals that put you to sleep. Here, I found a quote on about.com:

Caffeine mimics adenosine, and binds to all the adenosine receptors in
your brain. This prevents the real adenosine from doing its job, which
happens to be the slowing down of nerve impulses and the causing of
drowsiness. So your brain becomes more alert. Caffeine also increases
the levels of dopamine in your brain, which improves your feeling of
well-being and improves your mood.

As I was looking for negative reports about caffeine, I found a lot of
new age tree-hugging wannabe pseudo-science.  A lot of people try to
sell you a lot of weird things to drink instead of coffee. I expect that
Teeccino, Golden Fields coffee substitutes, bambu coffee substitute,
ginseng tea...i bet all of these are really big in California. I'll
stick with folgers or Millstone kona.

It amazes me that people who avoid caffeine drink tea, which has large
quantities of a theobromine, a stimulant which is (incidentally) lethal
to dogs.

  <snip>

  I suppose by definition, "too much" of anything isn't "good." But so
what?

  Limit coffee intake to no more than 4 cups a day, stop drinking
coffee at least 4 hours before bedtime, and coffee is for most is
otherwise a completely compatible activity within the context of an
otherwise healthy daily routine.

  Recent studies show coffee apparently protects alcohol drinkers from
liver damage, imparts antioxidant effects, increases energy and
alertness, and provides hydration (like pure water). A nice hot cup of
coffee is good stuff. Just my opinion.

Wow, you're pretty smart, aren't you?

So you mean when you consume enough of something so that it's "not
good", you are consuming "too much"?

Has this relationship been "not good" and "too much" been studied
somewhere, or is this your original research?

Drinking too much water is not good for you.

Your point?