Illinois

and you must obtain written confirmation from your physician that you have one of the following debilitating conditions, and that you have been diagnosed in office, and that you are under that physician's care for the treatment of the condition. Otherwise, if you have headaches or backaches, fuhgeddaboudit.

Acquired Immunodeficiency Syndrome (AIDS)
Agitation of Alzheimer's disease
Amyotrophic Lateral Sclerosis (ALS)
Arnold-Chiari malformation and Syringomelia
Cachexia/wasting syndrom
Cancer
Causalgia
Chronic Inflammatory Demyelinating Polyneuropathy
Crohn's disease
CRPS (Complex Regional Pain Syndromes Type II)
Dystonia
Fibromyalgia (severe)
Fibrous dysplasia
Glaucoma
Hepatitis C
Human Immunodeficiency Virus (HIV)
Hydrocephalus
Interstitial Cystitis
Lupus
Multiple Sclerosis
Muscular dystrophy
Myasthenia Gravis
Myoclonus
Nail-patella syndrome
Neurofibromatosis
Parkinson's disease
Post-concussion syndrome
RSD (Complex Regional Pain Syndromes Type I)
Residual limb pain
Rheumatoid arthritis (RA)
Seizures, including those characteristic of epilepsy (Starting January 1, 2015)
Sjogren's syndrome
Spinal cord disease, including, but not limited to, arachnoiditis, Tarlov cysts, hydromyelia, syringomyelia
Spinal cord injury
Spinocerebellar Ataxia (SCA)
Tourette’s syndrome
Traumatic brain injury (TBI)

http://www.idph.state.il.us/HealthWellness/MedicalCannabis/faq.htm