In general, clients can buy Ritalin online with or without a prescription anywhere in the world. This medication treats attention deficit hyperactivity disorder. It works by adjusting the quantities of certain chemical substances in the brain. Methylphenidate belongs to the stimulant drug category. It can help you increase your ability to pay attention, stay focused during a task, and retain behavioral control. It may also help with workplace organization and the development of listening skills. This medicine is also used to treat a specific sleep disorder called narcolepsy. Ritalin (methylphenidate) is a stimulant medication. It treats narcolepsy as well as Attention Deficit Hyperactivity Disorder (ADHD).