What happens if consume too much cocoa powder?

Answer 1

Assuming you're referring to powdered cocoa (not a drink composite that contains lots of things), the items you'll be interested in are caffeine and theobromine.

In humans, theobromine doesn't really seem to do a lot. Double blind tests failed to show humans' ability to identify the theobromine from the placebo, either via perception or vital statistics.

Caffeine on the other hand was identified 100% of the time. Caffeine is a cardiac stimulant, tends to increase dehydration, keeps us alert, and seems to make us feel a sense of well-being. Clinical caffeine overdoses are rare, and more likely seen with caffeine in tablet form than in either coffee or chocolate/cacao.

Note that dogs and cats react strongly to theobromine -- it's a serious toxin for them and probably is responsible for the overall majority of canine poisonings in the US and Europe.