How is caffeine harmful to humans?!

Caffeine increases the heart rate. Excessive consumption over a long period can cause serious damage to the heart. It can also irritate the bladder and cause infections in the urine (as I have experienced myself after drinking alot of energy drinks and fresh coffee). It affects the skin, causing dark circles under the eyes inparticularly. And if the body has too much in one go, it causes dizziness, nausea, headaches, mood swings/irritability and shakes. This can also occur when you are dependent on caffeine and go through withdrawal. :-)

Here are some sources.

Like most things, caffeine is fine- even good- in small amounts but dangerous in excess.

http://www.marksdailyapple.com/coffee-te…
http://www.marksdailyapple.com/caffeine-…
http://www.marksdailyapple.com/the-dope-…

It can disrupt your nervous system and cause dizziness...