Alkaloids are a group of natural organic compounds that contain nitrogen and have a strong physiological effect on the body. They are found in a variety of plants, especially in the poppy, nightshade, leguminous and rue families. Alkaloids often have pronounced biological effects that can be both therapeutic and toxic, depending on the type of compound and dose. Notable examples include morphine, caffeine, quinine, strychnine, and atropine.
These substances are widely used in medicine, pharmaceuticals and folk medicine. Some alkaloids, such as morphine, are used as pain relievers, while others, such as caffeine, have a stimulating effect. There are also alkaloids with antiparasitic, antimalarial, antispasmodic or neurotoxic effects. Proper application and dosage are extremely important, as many alkaloids can be dangerous if overdosed or misused.