Numerous medical conditions may be triggered by diet Coke consumption. According to the Green Facts website, aspartame is a non-caloric sweetener used in many diet soft drinks -- including diet Coke -- and food preparations 1. Although several national and international organizations have established an acceptable daily intake value, other institutions have alleged that aspartame causes or contributes to certain long-term medical conditions. According to the New York Times, aspartame is one of the most contentiously debated food and beverage additives 2.

Multiple Sclerosis

Consumption of diet Coke may trigger multiple sclerosis in some individuals. According to the National Institute of Neurological Disorders and Stroke, or NINDS, multiple sclerosis is an unpredictable central nervous system disease that disrupts communication between your brain and other parts of your body. Some investigators believe that multiple sclerosis is an autoimmune disease in which your body's immune system attacks the protective sheath surrounding your nerves. Possible causes or triggers associated with multiple sclerosis include consumption of aspartame, genetics and childhood viral infections. Common signs and symptoms associated with multiple sclerosis include:

• numbness or weakness in one or more limbs
  
• partial or complete vision loss
  
• a tingling sensation throughout your body
  
• dizziness
  
• fatigue
  
• tremors
  
• lack of coordination
  
• unsteady gait

Epilepsy

Epilepsy is a medical condition that may be triggered by the consumption of diet Coke and aspartame. The Natural News website states that aspartame has been known to trigger convulsions and grand mal seizures in certain individuals 3. According to MayoClinic.com, epilepsy is a disorder that develops from the production of electrical signals inside your brain that cause recurring seizures 4. Approximately 1 percent of Americans will experience an unprovoked seizure at some point in their lives. To have epilepsy, however, you need to have had at least two unprovoked seizures. Common signs and symptoms associated with epilepsy include temporary confusion, a staring spell, violent, uncontrollable jerking movements of your arms and legs or a complete loss of consciousness. Possible complications associated with epilepsy include falling, drowning, car accidents and certain birth defects.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a medical condition that may be triggered by the consumption of diet Coke and aspartame. According to the Centers for Disease Control and Prevention, or CDC, chronic fatigue syndrome is a debilitating and complex disorder in which you feel overwhelming fatigue that is not helped by rest. Physical or mental exertion can increase your fatigue if you have chronic fatigue syndrome. The CDC states that the cause or causes of chronic fatigue syndrome have not been determined. However, dietary triggers, such as the consumption of aspartame, may play a role.