Common Name: Red Maple
Scientific Name: Acer rubrum (Aceraceae)

Red maple trees, found throughout the eastern United States and Canada, are not entirely toxic to pets. It is the leaves of the red maple tree that are dangerous. Specifically, the leaves must be dried or wilted, like those found on a snapped branch after a high wind storm. The dead leaves that fall in Autumn and the leaves on a live tree pose no threat.

Horses are the species indicated for this toxicity.

Signs and symptoms of toxicity: Clinical signs often develop 12-48 hours following ingestion. Death may occur 3-6 days post-ingestion. Signs of toxicity include depression, fatigue, refusal to eat, abdominal pain, decreased heart rate, difficulty breathing, fever, and discolored mucous membranes.

Toxic consumption: The minimum threshold for toxicity is not known and suspected consumption should be reported immediately. Death occurs in 60-65% of cases.

References:
– Alward A, Corriher CA, Barton MH, et al. Red maple (Acer rubrum) leaf toxicosis in horses:a retrospective study of 32 cases. J Vet Intern Med 2006;20:1197-1201.
– George LW, Divers TJ, Mahaffey EA, et al. Heinz body anemia and methemoglobinemia in ponies given red maple (Acer rubrum L.) leaves. Vet Pathol 1982;19:521-533.