To be eligible for enrollment in this study, subjects must meet the following eligibility criteria within fourteen days prior to randomization:

Inclusion criteria:

• A clinical diagnosis of laboratory-supported probable, probable or definite ALS, according to modified EL Escorial criteria.
• FVC greater or equal to 75% of predicted.
• Onset of weakness within 3 years prior to enrollment.
• If patients are receiving riluzole they must be on a stable dose for at least the past thirty days.
• Women of childbearing age must be non-lactating and surgically sterile or using an effective method of birth control and have a negative pregnancy test (adequate birth control includes use of intra-uterine device or oral contraceptives plus a barrier method, e.g. condom, diaphragm).
• Willing and able to give signed informed consent that has been approved by your Institutional Review Board (IRB).

Exclusion criteria:

• Requirement for tracheotomy ventilation (or non-invasive ventilation > 23 hours/day).
• Diagnosis of other neurodegenerative diseases (Parkinson's disease, Alzheimer's disease, etc).
• FVC < 75% of predicted.
• A clinically significant history of unstable medical illness (unstable angina, advanced cancer, etc) over the last 30 days.
• History of renal disease (screening creatinine greater than 1.5).
• History of liver disease (screening alanine aminotransferase greater than 3 times the upper limit of normal).
• History of hematologic disease (screening white blood cell count less than 3,800/mm3).
• History of system lupus erythematosis (or screening ANA of 1:160 or greater).
• Treatment with any medications that may cause lupus-like symptoms within 4 weeks of baseline visit (e.g. procainamide, hydralazine).
• History of vestibular disease (excluding benign position vertigo).
• Pregnancy or lactation.
• Allergy to tetracycline antibiotics.
• Use of minocycline within thirty days of enrollment (baseline visit).
• Use of anti-epileptic medications other than gabapentin.
• Limited mental capacity rendering the subject unable to provide written informed consent or comply with evaluation procedures.
• History of recent alcohol or drug abuse or noncompliance with treatment or other experimental protocols.
• Use of any investigational drug within the past 30 days (Creatine, Vioxx, Celebrex, Topiramate).
• Women with the potential to become pregnant who are not practicing effective birth control.