Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease that causes the death of 30,000 affected individual every year. Complex nature and unknown pathogenesis of this disease are 2 major reasons for failure of therapeutic interventions. Edaravone is a free radical scavenger that slows down functional decline and prevents from disease progression in ALS patients. FDA newly approved this drug in these patients (2017/5/5). In this study, investigators aimed to assess the treatment effect of this newly approved drug in patients with ALS in a representative Iranian population.

Inclusion Criteria:

1. Patients diagnosed as definite or probable ALS according to El Escorial Criteria.
2. ALS patients who are graded as mild or moderate according to ALS Health State Scale.
3. Forced vital capacity of at least 80%
4. Desire of the patient to participate in this study and Signing Written Informed Consent.

Exclusion Criteria:

1. Incidence of drug's side effects that requires discontinuation of the drug (Edaravone's side effects: Acute kidney injury, Acute allergic reactions, DIC, Thrombocytopenia, Leukopenia).
2. Desire of the patient to discontinue participating in this study.
3. the patient starts another drug or herb for ALS during the study.