May have an antidepressant effect which could interfere with medication.
– J Pharm Sci 1992 Jul;81(7):620-1 — An antidepressant principle of Lobelia inflata L. (Campanulaceae). — Subarnas A, Oshima Y, Sidik, Ohizumi Y.

Results suggest that beta-amyrin palmitate, from lobelia, might possess a sedative action.
– J Pharm Pharmacol 1993 Jun;45(6):545-50 — Pharmacological properties of beta-amyrin palmitate, a novel centrally acting compound, isolated from Lobelia inflata leaves. — Subarnas A, Tadano T, Oshima Y, Kisara K, Ohizumi Y.

Lobelia may have harmful effects and is potentially toxic.

– Tex Med 2001 Jun;97(6):64-8 — Use of alternative and complementary therapies for pediatric asthma. — Mazur LJ, De Ybarrondo L, Miller J, Colasurdo G.

May cause vomiting.
– Arch Immunol Ther Exp (Warsz) 1980;28(5):777-82 — Studies on vomitory effect of some acridine compounds. — Kowalczyk-Bronisz SH.