Fentanyl, also spelled fentanil, is an opioid that is intended to be used as a pain reliever and anaesthetic, but which has become popular as a recreational drug, leading to mass addictions in the US and elsewhere. Production of fentanyl has taken place in China and other countries, but has come under scrutiny by several national governments, including Beijing, which on April 1, 2019, announced a ban on production of all variants of fentanyl.