Which plant is associated with pulmonary toxicosis?

• A. rape + canola (brassica)
• B. red maple (acer)
• C. sweet potato (ipomea)
• D. purple mint or beefsteak plant (perilla)

Answer: (D)

Pulmonary toxicosis from plants is caused by toxins that injure the lung’s alveolar-capillary system, leading to edema and hemorrhage and rapid breathing in affected animals. Beaufool with the beefsteak plant, Perilla frutescens, is the classic source of this syndrome in cattle. It contains perilla ketone, a volatile toxin that, when ingested or inhaled from forage or hay contaminated with Perilla, damages the airways and alveoli and drives acute pulmonary edema and emphysema. Animals grazing on contaminated pastures or fed hay containing this plant commonly develop sudden respiratory distress and can die without prompt removal of the toxin and supportive care. The other plants listed tend to cause different problems—red maple is known for oxidative damage and hemolysis in horses, while rape and canola are more associated with other toxic effects like photosensitization or digestive upset—so they are not the typical culprits for pulmonary toxicosis.