The term "sweet pea" can be a significant source of confusion, as it refers to two very different plants. The true sweet pea, of primary concern for pet toxicity, is Lathyrus odoratus. This is a flowering annual climbing plant, prized in gardens for its fragrant and colorful blossoms. It is a member of the Fabaceae (legume) family. It is crucial to distinguish this ornamental plant from the edible garden pea, which is typically from the species Pisum sativum. The pods and peas of Pisum sativum are non-toxic and often found in pet food. However, the ornamental sweet pea (Lathyrus odoratus) is not safe for consumption.
The toxicity of the ornamental sweet pea plant is attributed to a compound called beta-aminopropionitrile. This substance is the primary toxic agent found predominantly in the seeds (peas) and the seed pods, though the entire plant is considered toxic if ingested in large enough quantities. Beta-aminopropionitrile can interfere with the normal function of connective tissue and bone formation. In a condition known as lathyrism, it can cause weakness, paralysis, and even death in severe cases by affecting the neurological system. The concentration of this toxin is highest in mature seeds.
Both dogs and cats are at risk of poisoning from ingesting the ornamental sweet pea plant. The seeds pose the greatest danger due to their high concentration of toxin. A dog or cat that chews on or consumes the seeds or seed pods may exhibit symptoms of poisoning. It is important to note that even a small number of seeds can be harmful, especially to smaller animals. The plant's attractive seed pods may intrigue pets, making them a potential hazard in gardens or homes with cut flowers.
If a pet ingests part of an ornamental sweet pea plant, symptoms may not appear immediately. The onset can be delayed. Key clinical signs to watch for include: lethargy, vomiting (which may contain plant material or seeds), diarrhea, tremors, and loss of coordination (ataxia). In more severe cases, the neurotoxic effects can lead to seizures, weakness or paralysis of the hind limbs, and an elevated respiratory rate. The condition can be progressive if a significant amount of toxin is ingested.
If you suspect your dog or cat has ingested any part of an ornamental sweet pea plant, you should contact your veterinarian or an animal poison control center immediately. Time is a critical factor. Be prepared to identify the plant (Lathyrus odoratus) and estimate how much your pet may have consumed. Treatment is primarily supportive, as there is no specific antidote for this toxin. A veterinarian may induce vomiting if the ingestion was very recent, administer activated charcoal to prevent further absorption of the toxin, and provide intravenous fluids and medications to control neurological symptoms like seizures.
