Fentanyl is an extremely powerful, fast-acting, synthetic opioid. It is a leading cause of drug overdose deaths in the United States. Fifty to 100 times more potent than morphine and 30 to 50 times more potent than heroin, fentanyl can kill even in very small doses and is more addictive than heroin. Although it may be safely used when administered by doctors, it is very easy to overdose on a small amount of fentanyl. Worse, illicit drug dealers often combine fentanyl into other drugs such as cocaine and heroin, meaning users of street drugs never really know whether or not what they're getting contains this deadly substance. In many cases, the illicit drug sellers themselves don't know what's in the product they push. Fentanyl is indeed a very "High-Risk High," but knowing the dangers and what to watch out for can help keep you safe.