There are over 92 different health side effects associated with aspartame consumption ranging from abdominal pain to migraines, dizziness and hives.
Aspartame is a popular sugar substitute that can be found in diet soda drinks, chewing gum, fruit spreads and sugar-free products to name a few. It is also known by the brand names Sweet One, NutraSweet and Spoonful. The components of aspartame can lead to a number of health problems and the side effects can occur gradually, can be immediate, or can be acute reactions.
There is a seemingly endless list of side effects from aspartame ingestion. Adverse reactions and side effects of aspartame include:
Visual:
Blindness in one or both eyes, decreased vision and/or other eye problems such as: blurring, bright flashes, squiggly lines, tunnel vision, decreased night vision, pain in one or both eyes, decreased tears, trouble with contact lenses, and bulging eyes
Ear:
Tinnitus – ringing or buzzing sound, severe intolerance of noise and marked hearing impairment
Neurologic:

Epileptic seizures, headaches, migraines, dizziness, unsteadiness, confusion, memory loss, severe drowsiness and sleepiness, paresthesia or numbness of the limbs, severe slurring of speech, severe hyperactivity, restless legs, atypical facial pain and severe tremors
Psychological/Psychiatric:

Severe depression, irritability, aggression, anxiety, personality changes, insomnia and phobias
Chest:
Palpitations, tachycardia, shortness of breath and new onset high blood pressure

Gastrointestinal:

Nausea, diarrhea, blood in stools, abdominal pain, and pain when swallowing
Skin and Allergies:

Itching without a rash, lip and mouth reactions, hives, and aggravated respiratory allergies such as asthma
Endocrine and Metabolic:

Loss of control of diabetes, menstrual changes, marked thinning or loss of hair, marked weight loss, gradual weight gain, aggravated low blood sugar (hypoglycemia) and severe PMS
To keep yourself safe from contracting ‘artificial sweetener syndrome,’ it is suggested that you stop taking all products containing this chemical.
Sources:
http://www.sweetpoison.com/aspartame-side-effects.html
http://www.naturalnews.com/035126_aspartame_side_effects_withdrawal.html