There are so many:
Rare

Anxiety
bleeding gums
blistering, peeling, or loosening of the skin
blood in the urine or stools
bloody, black, or tarry stools
cough
difficulty breathing
discouragement
fast, irregular, pounding, or racing heartbeat or pulse
feeling sad or empty
irritability
lack of appetite
loss of interest or pleasure
noisy breathing
pinpoint red spots on the skin
seeing, hearing, or feeling things that are not there
seizures
swelling around the eyes
tightness in the chest
trouble concentrating
trouble sleeping
unusual bleeding or bruising

Agitation
blistering, peeling, or loosening of the skin
burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
chest pain
chills
clay-colored stools
dark urine
diarrhea
difficulty swallowing
dizziness or fainting
fever
general feeling of tiredness or weakness
headache
high fever
hives, itching, skin rash
hoarseness
joint or muscle pain
large, hive-like swelling on face, eyelids, lips, tongue, throat, hands, legs, feet, or genitals
light-colored stools
lower back or side pain
nausea
painful or difficult urination
pale skin
puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
red skin lesions, often with a purple center
red, irritated eyes
sore throat
sores, ulcers, or white spots in the mouth or on the lips
stomach pain
swollen glands
unpleasant breath odor
unusual tiredness or weakness
upper right abdominal pain
vomiting of blood
yellow eyes or skin

Less common
Difficulty having a bowel movement

Rare
Bad, unusual, or unpleasant (after) taste
bone or muscle pain
change in taste
continuing ringing or buzzing or other unexplained noise in the ears
decreased interest in sexual intercourse
difficulty in moving
dry mouth
dry skin
feeling of warmth
hearing loss
inability to have or keep an erection
lack or loss of strength
loss in sexual ability, desire, drive, or performance
muscle pain or stiffness
redness of the face, neck, arms and occasionally, upper chest
redness of the white part of the eyes
stomach discomfort
unusual drowsiness

I read the pamphlet that came with it and it made me so afraid to take it. The side effects are crazy!