Eclectic physicians generally recommended using a tincture of lobelia made partially or entirely with vinegar instead of alcohol. A vinegar extract is known as an acetract. The absolute maximum amount to take should be that which causes no, or minimal, nausea. Lobelia ointment has also been used topically on the chest to relieve asthma and bronchitis . People should apply such ointments liberally several times per day.
Lobelia frequently causes nausea and vomiting when the amount used is too high.
Generally, more than 1 ml of tincture or acetract taken at one time will cause nausea and possibly vomiting and should be avoided. Although lobelia has a reputation for being toxic, a thorough review of the medical literature was unable to find any well-documented case of serious problems or death due to lobelia. This may be because a toxic amount cannot be ingested without first causing vomiting. Signs of lobelia poisoning are said to include weakness, heartburn, weak pulse, difficulty breathing, and collapse. Nevertheless, lobelia should not be used for more than one month consecutively and should be avoided during pregnancy and lactation.