Hyoscine

Hyoscine, also known as scopolamine, is a medication used to treat motion sickness and postoperative nausea and vomiting. Hyoscine works by blocking some of the effects of acetylcholine within the nervous system. It can cause central nervous system depression, which can lead to a decreased rate of breathing, decreased heart rate and loss of consciousness possibly leading to coma or death.

Characters poisoned with Hyoscine

 * Sir Claud Amory - Black Coffee

Hyocine in adaptations

 * Appointment with Death (1988 film) - Sarah King prescribes hyocine for Poirot on the sea voyage to the Holy Land.