• (n.) An alkaloid obtained from the yellow jasmine (Gelsemium sempervirens), as a bitter white semicrystalline substance; -- called also gelsemia.
Gel'se·mine noun (Chemistry) An alkaloid obtained from the yellow jasmine ( Gelsemium sempervirens ), as a bitter white semicrystalline substance; -- called also gelsemia . 
Type: Term Pronunciation: jel′sĕ-mēn Definitions: 1. A crystallizable alkaloid derived from gelsemium (yellow jasmine); a mydriatic and central nervous system stimulant.