When someone experiences an overdose, their body becomes overwhelmed by the toxic effects of the substance they've consumed. Learn more. Overdose happens when someone consumes a toxic amount of one or multiple drugs. An overdose is a medical emergency, so if you think that you or another person is experiencing an overdose, it is critical to call 911 immediately. Drug overdose is sometimes used as a means to commit suicide, as the result of intentional or unintentional misuse of medication. Intentional misuse leading to overdose can include using prescribed or non-prescribed drugs in excessive quantities in an attempt to produce euphoria. CDC works to prevent drug overdose, the leading cause of injury-related death in the United States. Learn the identifying signs and symptoms of a drug overdose so that you can get the help you or a loved one needs and possibly save a life. If you believe someone is experiencing a drug overdose, please stop reading and seek medical attention. Overdoses are considered a medical emergency and, in many cases, can be a potentially life-threatening situation. Find overdose prevention and intervention resources for public health professionals. Information on overdose prevention strategies and partnerships for healthcare professionals. Preventing drug overdose and reducing substance use-related harms is a CDC priority.