Scopolamine, also known as hyoscine, or Devil's Breath, is a natural or synthetically produced tropane alkaloid and anticholinergic drug that is used as a medication to treat motion sickness and postoperative nausea and vomiting. It is also sometimes used before surgery to decrease saliva. When used by injection, effects begin after about 20 minutes and last for up to 8 hours. It may also be used orally and as a transdermal patch since it has been long known to have transdermal bioavailability.

Scopolamine is in the antimuscarinic family of drugs and works by blocking some of the effects of acetylcholine within the nervous system. Scopolamine was first written about in 1881 and started to be used for anesthesia around 1900. Scopolamine is also the main active component produced by certain plants of the nightshade family, which historically have been used as psychoactive drugs (known as deliriants) due to their antimuscarinic-induced hallucinogenic effects in higher doses. In these contexts, its mind-altering effects have been utilized for recreational, criminal and occult purposes. The name "scopolamine" is derived from one type of nightshade known as Scopolia, while the name "hyoscine" is derived from another type known as Hyoscyamus niger. It is on the World Health Organization's List of Essential Medicines.