The active compound in lobelia is lobeline, which has a similar activity in the body to nicotine. This explains its attempted use as an aid in smoking cessation. Like nicotine, lobelia stimulates the central nervous system (CNS), dilates lung passage ways, and increases respiration rate. However at higher doses, lobelia has the opposite effect and causes CNS depression and reduced breathing rate.
In experiments with rats and mice, lobeline increased the release of stimulatory neurotransmitters dopamine and norepinephrine from specific parts of the brain, but it is still unclear what significance this has in the human body. Lobeline can have both additive and opposing effects when used at the same time as nicotine.
Data in humans are limited. A review of studies as well as a large multicenter trial do not support its use for smoking cessation.