The main therapy for Parkinsons disease is the drug levodopa, also called L-dopa. It is a simple chemical found naturally in plants and animals. Nerve cells use levodopa to make dopamine to replenish the brains supply. Levodopa helps to reduce tremors and other symptoms of Parkinsons disease during the early stages of the disease. It allows most people with Parkinsons to extend the period of time in which they can lead relatively normal, productive lives. 
What is (are) Parkinsons Disease ?