scopolamine,alkaloiddrug obtained from a number of plants of the family Solenaceae, includingnightshade,henbane, andjimsonweed. Scopolamine is an effective remedy formotion sickness, probably because of its ability to depress the centralnervous system (brain and spinal cord). Likeatropine, it has adepressant action on parasympathetic nerves and in larger doses on autonomic ganglia. Scopolamine is also used to dry up secretions and dilate the bronchi duringanesthesia and to dilate thepupil during ophthalmological procedures. The drug is the most pharmacologically active of several alkaloid substances found inbelladonna, partly because of its greater solubility, which permits more rapid passage to the site of action.