Also found in: Medical.
Any of a group of toxic alkaloids, including atropine and scopolamine, found in plants such as belladonna and jimsonweed. These alkaloids are used in medicine in low doses to dilate the pupils of the eyes, dry respiratory passages, prevent motion sickness, and relieve cramping of the intestines and bladder.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.