Japanese maple trees are not toxic. In fact, the tree's leaves are eaten as part of some Japanese dishes and have no adverse health effects.
Japanese maples (Acer palmatum) are native to Japan, Korea and China. Gardeners and horticulturists prize these trees for their autumn colors and beautiful foliage. Japanese maples are typically small and perfect for small gardens or for growing in containers. Tree experts often refer to them as Acers.
There are more than 1,000 cultivars (or varieties) of Japanese maple trees. Similar species include Acer duplicatoserratum, Acer japonicum (Downy Japanese Maple), Acer pseudosieboldianum (Korean Maple), Acer shirasawanum (Fullmoon Maple), and Acer sieboldianum (Siebold's Maple).
None of these organizations list the Japanese maple (or Acer palmatum) or any of its similar species as toxic: ASPCA, Cat Fanciers Association (CFA), University of Illinois Veterinary Medicine Library and Cornell University's Department of Animal Sciences.
The Japanese maple may not be toxic, but a certain fungus that grows on the bark of red maple trees is; however, the Japanese maple comes from different parts of the genus than red maple, and this fungus does not grow on the Japanese maple.
It has been confirmed that red maple is toxic to horses. This has led some to consider all maple trees toxic; however, there have been no reports of Japanese maples being toxic to either animals or humans.