Parkinson's disease is a progressive nervous system disorder that causes tremors, muscle rigidity, and slow movement. It results from the loss of dopamine-producing nerve cells in the brain. Common symptoms include tremors, stiff muscles, slow movement, impaired facial expressions and speech, and poor balance. The exact causes are unknown, but it involves low dopamine levels. While there is no cure, treatment aims to manage symptoms through drugs or surgery. Adopting a Mediterranean diet may provide some protection, but more research is needed on prevention.