General Side Effects

• In general, caffeine will have few side effects other than an accelerated heart rate, wakefulness and an increased need to urinate.
  
  

Caffeinism

• When an individual regularly consumes a significant amount of caffeine (such as 600 milligrams per day, though caffeinism might result with less), she may experience anxiety, restlessness, sleep disorders, tremors and depression.
  
  

Gastrointestinal

• Some individuals experience gastrointestinal distress, diarrhea, nausea, vomiting and cramping after consuming caffeine.
  
  

Unusual Significant Symptoms

• Some individuals experience confusion, hives, itching, difficulty breathing, swelling of the mouth, tightness in the chest, cold or pale fingers and/or toes, dizziness, hallucinations, an irregular heartbeat, leg cramps or weakness, numbness or tingling of extremities, rectal sores, ringing in ears, seizure or a weak pulse.
  A doctor should be contacted if any of these symptoms are experienced.
  
  

Fibrocystic Breast Disease

• Fibrocystic breast disease has a positive correlation with caffeine consumption in women--consuming 31 milligrams to 250 milligrams of caffeine daily increases the odds of developing this disease by one and a half times.