Cats are naturally curious and may ingest plant materials, including tree leaves. While some leaves are harmless, many pose significant health risks, from mild gastrointestinal upset to severe, life-threatening poisoning.
Why Cats Chew on Leaves
Cats chew on leaves due to innate behaviors like curiosity, exploring their environment through taste and texture. Boredom, especially in indoor cats, can also lead them to seek plants for entertainment or stress relief. Some cats instinctively chew plants, like grasses, to aid digestion or pass hairballs, but this doesn’t imply a dietary need for tree leaves.
General Safety of Tree Leaves for Cats
Even non-toxic tree leaves can pose risks. Ingesting any plant material may cause mild gastrointestinal upset like vomiting or diarrhea, as cats lack the enzymes to fully digest plant matter, and fibrous leaves can irritate their digestive system. Since identifying tree species is challenging, it is generally best to prevent cats from consuming any leaves.
Common Toxic Tree Leaves for Cats
Many common tree leaves contain compounds that are highly toxic to cats. Awareness of these specific dangers is crucial for cat owners.
Oak leaves, particularly young leaves in spring or green acorns in fall, contain tannins that can cause poisoning. Ingesting these can lead to gastrointestinal signs such as vomiting, diarrhea, and abdominal pain. In some cases, oak toxicity can also result in kidney and liver impairment.
Cherry tree leaves, including those from wild cherry and chokecherry, are highly toxic as they contain cyanogenic glycosides. When ingested, these compounds release cyanide, which can prevent cells from absorbing oxygen. Symptoms of cherry poisoning include bright red gums, difficulty breathing, dilated pupils, drooling, vomiting, and even shock or death.
Wilted or dried red maple (Acer rubrum) leaves pose a significant threat. They contain a toxin that damages red blood cells, reducing oxygen-carrying capacity. While primarily a concern for horses, cats should be monitored for stomach irritation if ingested. Other maple species, like sycamore maple, can also be toxic.
Oleander (Nerium oleander) is extremely toxic; all parts, including leaves, contain cardiac glycosides. These toxins directly affect heart function, potentially causing life-threatening arrhythmias. Symptoms include excessive drooling, vomiting, diarrhea, weakness, muscle tremors, and abnormal heart rate.
Rhododendron and Azalea (Rhododendron spp.) leaves contain grayanotoxins, neurotoxins that interfere with nerve and muscle function, including the heart. Ingestion causes significant gastrointestinal upset like vomiting, diarrhea, and excessive drooling. More severe signs include weakness, low blood pressure, abnormal heart rhythms, coma, or death.
What To Do If Your Cat Eats a Potentially Harmful Leaf
If you suspect your cat has ingested a potentially harmful leaf, observe your cat closely for symptoms such as vomiting, diarrhea, lethargy, excessive drooling, difficulty breathing, or tremors. If possible, identify the plant your cat consumed, as this information is highly valuable for veterinary professionals. Immediately contact your veterinarian or an animal poison control center, such as the ASPCA Animal Poison Control Center at (888) 426-4435 or Pet Poison Helpline at (855) 764-7661. Do not attempt to induce vomiting unless specifically instructed by a professional, as it can sometimes cause further harm.
Preventing Cats from Eating Tree Leaves
Preventing cats from accessing tree leaves requires several strategies. For indoor cats, keep houseplants out of reach. Supervise outdoor access to prevent chewing on toxic trees. Provide safe alternatives like cat grass (oat, barley, or wheatgrass) to satisfy their chewing urge and offer fiber. Offer safe chew toys and engage in regular playtime to reduce boredom-driven plant chewing, and educate yourself on local toxic plants.