The use of nutritional supplements has almost doubled in the elderly population in the United States (US) in the past decade. We evaluated the use of nutritional supplements in Parkinson's disease (PD) patients to determine the prevalence of their use and whether patients were aware of possible side effects and drug interactions in the supplements they were taking. Consecutively selected PD patients from an academic movement disorders center completed a 33‐item questionnaire regarding their use of nutritional supplements. A total of 120 PD patients completed the questionnaire and were included in the data analysis (mean age ± SD = 68.2 ± 11.65 years, 67 [55.8%] men and 53 women). Seventy‐six patients (63%) took nutritional supplements at the time of data collection. Vitamins were the most common nutritional supplements used, and vitamin E was the most commonly used vitamin. Thirty‐six patients (47%) who took nutritional supplements consulted with their doctor before taking them, and only 4% of patients who took nutritional supplements were aware of possible side effects from their use. Twenty patients (16.7%) reported that they were currently taking nutritional supplements because of symptoms related to their Parkinson's disease. The vast majority of PD patients surveyed were not aware that nutritional supplements could cause adverse side effects. Less than half of the patients who took nutritional supplements consulted their physician before starting them. Greater awareness of nutritional supplement use in PD patients is warranted to avoid potentially harmful effects and drug interactions.