Yet the most widely used analgesics today are essentially folk remedies that have served for centuries: morphine and other opiates derive from the opium poppy, and aspirin comes from willow bark.

• 然而，今日最多人使用的止痛药，基本上是用了好几世纪的民间土方，譬如从罂粟花提炼出来的吗啡与其他鸦片类，以及从柳树皮萃取出来的阿斯匹灵。