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Philodendron
Philodendron spp., including 'Birkin'
Philodendron (Philodendron spp.), including popular varieties such as Philodendron Birkin, Heartleaf Philodendron, and Tree Philodendron, are widely kept houseplants toxic to cats. All Philodendron species contain insoluble calcium oxalate crystals (raphides) throughout their leaves and stems. Chewing releases these needle-like crystals into the oral tissue, causing immediate intense pain.
Important Notes
Toxic compounds: insoluble calcium oxalate raphides plus proteolytic enzymes in the sap
Mechanism: raphides mechanically penetrate the oral and GI mucosa; enzymes intensify the inflammatory response
Symptoms: sudden oral pain, intense drooling, pawing at mouth, swollen lips and tongue, difficulty swallowing, vomiting
All species and hybrids are equally hazardous — variegated varieties are no safer than plain green types
Rinse the mouth with water; seek veterinary care if throat swelling impairs breathing
Potentially Toxic Parts
Leaf
Possible Symptoms Reported in Cats
Edema (swelling) of the mouth, tongue, pharynx, and upper airways, leading to difficulty breathing (dyspnea)
Respiratory · Rapidly following ingestion
Renal failure, lethargy, excitability, nervous spasms, convulsions, and encephalitis
Gastrointestinal
Immediate oral pain, intense burning sensation, erythema
Gastrointestinal · Immediate
Excessive drooling (hypersalivation)
Gastrointestinal · Immediate
Vomiting, diarrhea, difficulty swallowing (dysphagia), and loss of appetite (anorexia)
Gastrointestinal · Shortly after ingestion.
Disclaimer: This summary was compiled from multiple sources and is for informational use only. It is not a diagnosis or treatment plan. Toxicity can vary based on the substance, amount, plant part, and individual cat. If you think your cat may have been exposed to a toxic substance, contact a veterinarian right away.