Alkaloid

Alkaloids are naturally occurring chemical compounds found mainly in plants. They often have strong effects on humans and animals because they can interact with nervous system receptors. Many alkaloids are used as medicines, such as painkillers like morphine or stimulants like caffeine, but some can be poisonous or have hallucinogenic properties. Plants produce alkaloids as a form of defense against pests or to help compete with other plants. Due to their powerful biological activity, alkaloids have long been important in medicine, recreational use, and research.