When someone experiences an overdose, their body becomes overwhelmed by the toxic effects of the substance they've consumed. Learn more. 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. In overdose, side effects become more pronounced, and other effects can take place, which would not occur with normal use. Large overdoses of some medications cause only minimal effects, while smaller overdoses of other medications can cause severe effects, possibly death. A drug-related overdose happens when someone takes too much of a drug – or a mix of drugs – and it overwhelms the body. This can be very dangerous or even deadly. 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. Get the most up-to-date fatal and nonfatal overdose data, including provisional overdose death estimates, through CDC's Overdose Prevention Data Channel. Poisoning occurs when someone or something (such as the environment) exposes you to dangerous chemicals, plants, or other harmful substances without your knowledge. An overdose may be mild, moderate, or serious. Symptoms, treatment, and recovery depend on the specific drug involved. Overdose (OD) happens when a toxic amount of a drug, or combination of drugs overwhelms the body. People can overdose on lots of things, including alcohol, Tylenol, opioids or a mixture of drugs. 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. 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.