1. The dried leaves and tops of Lobelia inflata (family Lobeliaceae); lobelia contains several alkaloids: lobeline, lobelamine, lobelanidine, lobelanine, norlobelanine, norlobelanidine, and isolobelanine. The fluid extract and the tincture have been used as an expectorant in asthma and chronic bronchitis. 2. One of a class of alkaloids isolated from lobelia. 3. Any plant of the genus Lobelia.