Although there is no known cure for essential tremor or Parkinson's disease (PD), medical treatment can often significantly reduce or eliminate functional disability. Mild essential tremor does not require treatment, and early treatment does not arrest or slow the natural progression in symptoms. When essential tremor interferes with daily activities, medical treatment options include beta blockers, anticonvulsants, benzodiazepines, and carbonic anhydrase inhibitors. Because of the great variability in the presentation of PD, no single approach is appropriate for all patients. Levodopa is the mainstay of pharmacologic therapy for PD, although other agents are indicated for monotherapy or in combination with levodopa. These include traditional and newer dopamine agonists, amantadine, anticholinergics, selegiline, and an emerging class of agents called COMT inhibitors.