Interestingly, pure caffeine is extremely toxic and must be handled with extreme safety. If this isn't enough to convince you, this is the warning label for pure caffeine:
WARNING! MAY BE HARMFUL IF INHALED OR SWALLOWED. HAS CAUSED MUTAGENIC AND REPRODUCTIVE EFFECTS IN LABORATORY ANIMALS. INHALATION CAUSES RAPID HEART RATE, EXCITEMENT, DIZZNESS, PAIN, COLLAPSE, HYPOTENSION, FEVER, SHORTNESS OF BREATH. MAY CAUSE HEADACHE, INSOMINA, NAUSEA, VOMITING, STOMACH PAIN, COLLAPSE AND CONVULSIONS. MAY CAUSE DIGESTIVE DISTURBANCES, CONSTIPATION, CARDIAC DISORDERS, AND DEPRESSION. MAY CAUSE EPIGASTRIC PAIN, CARDIAC AND RESPIRATORY DISORDERS, AND DEPRESSED MENTAL STATES. EYE CONTACT MAY CAUSE IRRITATION, REDNESS, AND CONJUNCTIVITIS. INGESTION MAY PRODUCE GASTROINTESTINAL IRRITATION, VOMITING, AND CONVOLUSIONS. FATALITIES HAVE BEEN KNOWN TO OCCUR.
Scary, eh?