Atropine is an alkaloid extracted from plants such as belladonna, datura, and hyoscyamine. Its sulfate is commonly used. The main alkaloids in belladonna are atropine and hyoscyamine. Datura is also called datura, and its roots, stems, leaves, flowers and fruits all contain atropine, hyoscyamine, scopolamine, etc.; the atropine component in the fruit can reach 8.33%. The alkaloids contained in the rhizomes of hyoscyamine are mainly hyoscyamine, atropine and scopolamine. This type of drug is rapidly absorbed by the gastrointestinal tract and can also be inhaled by local mucosa. Most of them are hydrolyzed and destroyed by liver enzymes. Within 24 hours, 4/5 of the atropine in the body is excreted in the urine, while scopolamine is excreted more slowly. Belladonna alkaloids are drugs for the anticholinergic reaction system, which can block the reactions caused by many cholinergic postganglionic fibers. Atropine can mildly excite higher nerve centers, the hypothalamus and the medulla oblongata, especially motor and speech functions, but large doses can turn the central nervous system from exciting to inhibiting. The therapeutic dose of scopolamine has a sedative effect, but can excite the respiratory center. Atropine can counteract the vasodilation and sudden drop in blood pressure caused by cholinergic drugs. Atropine and scopolamine strongly inhibit the secretion of sweat glands, salivary glands, lacrimal glands, bronchial glands, etc.; make the iris sphincter and ciliary muscle ineffective on the cholinergic nerves, causing pupil dilation and increased intraocular pressure.