Peonies belong to the genus Paeonia, which is the only genus in the family Paeoniaceae. These popular garden perennials are prized for their large, showy, and often fragrant blooms. From a botanical perspective, it is important to identify which parts of the plant contain the compounds of concern. The entire peony plant, including the roots, leaves, stems, and flowers, contains paeonol and other potentially irritating compounds. However, the highest concentration of these toxins is typically found in the root bark.
The primary toxic agent in peonies is a compound known as paeonol. Additionally, peonies contain oxalates, specifically calcium oxalate crystals. These microscopic, needle-shaped crystals are a common defense mechanism in many plants. When plant material is chewed or ingested, these crystals can be released, causing immediate irritation and injury to the soft tissues of the mouth, tongue, throat, and gastrointestinal tract. The combination of these compounds classifies the peony as toxic, though generally considered to be of mild to moderate toxicity.
When a pet, such as a dog or cat, chews on or ingests any part of a peony plant, the calcium oxalate crystals act as mechanical irritants. They embed themselves in the oral mucosa, causing intense pain and swelling. This often prevents further ingestion, as the animal will typically stop chewing due to the immediate discomfort. If significant material is swallowed, the irritation can extend through the entire digestive system. The paeonol compound can contribute to systemic effects. Common clinical signs of peony poisoning include vomiting (which may contain blood), diarrhea, depression, lethargy, and excessive drooling or pawing at the mouth due to oral pain.
The severity of the poisoning is directly related to the amount of plant material consumed relative to the size of the animal. A large dog that nibbles a single leaf may experience only mild, self-limiting gastrointestinal upset. In contrast, a small cat that consumes a larger quantity, particularly of the roots, could face more serious consequences, including dehydration from persistent vomiting and diarrhea. While peony toxicity is rarely fatal, it is a condition that necessitates veterinary consultation. A veterinarian can provide supportive care, such administering medications to control vomiting and nausea, offering gastro-protectants, and providing intravenous fluids to prevent dehydration and aid recovery.
