Lobelia species

CARDINAL FLOWER, PALE SPIKE LOBELIA, BLUE CARDINAL FLOWER

Images on this page contributed by: Ann F. Rhodes, PhD, Director of the Pennsylvania Flora Project

Description

Lobelias are herbs, annual or perennial plants, that grow to 3-4 feet tall. Leaves are alternate. Flowers range from scarlet to light blue.

Geographic range

Lobelias thrive in moist, fertile soil in most of the southern United States.

Toxic principle

Pyridine alkaloids similar to nicotine are found within the plant. Lobeline is common to most species.

Toxicity

Poisonous to cattle, sheep, and goats, lobelia also affects humans. Intoxication usually occurs in late winter to early spring. In sheep, a dose of 0.6 - 2.2% body weight may cause development of clinical signs within one to two days and death in three to nine days.

Mechanism of toxicologic damage

Lobeline stimulates the carotid body, decreasing heart rate and often causing arrhythmias.

Diagnosis

Clinical signs

Clinical signs include excessive salivation, vomiting, diarrhea, and dilated pupils. Corneal and oral ulceration may be seen. Coma and death, possibly due to cardiopulmonary arrest, has been seen.

Laboratory Diagnosis

During the first several hours of intoxication, marked elevation of serum hepatic enzyme activity (AP, AST) may be seen.

Lesions

Brain and lung congestion, splotchy hemorrhages, and excess reddish peritoneal fluid may be found. Ulceration of the mucosa of the rumen and abomasum may be extensive.

Treatment

No specific treatment. Atropine may relieve some of the signs. Mineral oil and saline laxatives, if given soon after ingestion, may decrease absorption of the toxins.

Read more in the Poisonous Plants of Pennsylvania Publication