This section is from the "A Handbook of Useful Drugs" book, by State Medical Examining and Licensing Boards.
The dried leaves and tops of Lobelia inflata. Occasionally administered in the form of powder.
Action and Uses: Lobelia has almost the same action as nicotin. Small doses stimulate, and large doses paralyze, the respiratory center. The vagus endings in the bronchial muscles are also depressed and the bronchi are relaxed. Small doses taken continuously cause a persistent quickening of the pulse; moderate doses produce nausea and large doses produce vomiting with marked and dangerous collapse.
Lobelia is no longer used as an emetic. As an expectorant it may be employed to increase bronchial secretion, but it must be used with caution. It is chiefly used for the treatment of bronchial asthma, in which it often renders distinct service. It should never be employed in asthma due to or associated with heart disease.