Buy Ritalin Online with fast and secure delivery. Ritalin is a central nervous system stimulant. Methylphenidate affects chemicals in the brain and nerves that contribute to hyperactivity and impulse control. It is used to treat attention deficit disorder (ADD), attention deficit hyperactivity disorder (ADHD), and narcolepsy. Ritalin should be used as a part of a total treatment program for ADHD that may include counseling or other therapies.