...body as a whole
- difficulty sleeping
- muscle twitching
- confusion
- in and out of consciousness
- increased urination
- increased thirst
- death
- fever
...respiratory
- difficulty breathing
...gastrointestinal
- vomiting
- diarrhea
...heart and blood vessels
- irregular heartbeat
- rapid heart beat
...nervous system
- hallucinations
- dizziness
- convulsions
"In most cases an overdose of caffeine will not kill you. However, it can be fatal. A lethal dose is estimated at 10 grams. However, a toxic dose will vary from person to person."
Probably not a nice way to go...