Begonias: A Harmful Toxin to Cats
Chemical Structure & Breakdown
Begonias are popular ornamental plants known for their vibrant flowers and foliage. However, they contain insoluble calcium oxalates, which are concentrated in the plant’s tubers. These oxalates are crystalline compounds that, when ingested, can cause irritation to the mucous membranes, particularly in the mouth, throat, and digestive tract.
At the cellular level, insoluble calcium oxalates are needle-like crystals (raphides) that cause mechanical irritation when they come into contact with soft tissues. When chewed, these crystals embed into the oral tissues, causing immediate discomfort and inflammation. Although the toxin is not absorbed systemically in large amounts, the physical damage caused by the crystals can be painful and distressing to cats.
Toxin Metabolism
In cats, ingestion of begonias leads to the release of calcium oxalate crystals in the mouth and throat, causing immediate irritation. The toxin primarily acts locally by physically damaging the tissues of the oral cavity and digestive tract, leading to drooling, vomiting, and difficulty swallowing. Although these crystals are not easily absorbed into the bloodstream, they can still cause significant gastrointestinal distress.
Symptoms of begonia toxicity in cats include drooling, vomiting, pawing at the mouth, difficulty eating or swallowing, and oral swelling. In severe cases, ingestion of large amounts of the plant, particularly the tubers, can lead to dehydration due to vomiting and refusal to eat. Treatment usually involves decontamination, such as rinsing the mouth with water, and providing supportive care like intravenous fluids to manage symptoms and prevent dehydration.
Additional Plants or Items Containing the Toxin
- Begonia spp. (Begonias, especially the tubers)
- Philodendron spp.
- Dieffenbachia spp. (Dumb Cane)
- Caladium spp. (Elephant Ear)
These plants contain insoluble calcium oxalates, which can cause significant irritation to cats if ingested, particularly affecting the mouth and throat.
