It is a strong relaxant and works well to bring down fevers. Surrounded by controversy of it's toxicity, lobelia should be used with caution in only small amounts under the advisement of a qualified Herbalist. The whole plant is harvested when the lower fruits are ripe. It may be used in many conditions in combination with other herbs. Lobelia has been used medicinally as an expectorant, anti-asthmatic, stimulant, antispasmodic, diaphoretic, diuretic, and nervine.
Lobelia seems to affect the nervous system.
It also acts as an emetic but in small amounts can calm the stomach. Externally, the plant is used in treating pleurisy, rheumatism, tennis elbow, whiplash injuries, boils and ulcers. Lobelia, after it has been chewed, tastes similar to tobacco and produces effects like those of nicotine. These similarities account for the plant's having been called Indian tobacco and for reports of its stimulatory and depressant activity. It has a general depressant action on the central and autonomic nervous system and on neuro-muscular action.