The shamrock plant (Oxalis spp.) can be toxic to cats. Oxalates in the plant are absorbed by the cat's gastrointestinal system, and travel to the kidneys. In the kidneys, oxalic acid combines with calcium, forming calcium oxalate crystals, according to Centennial Valley Animal Hospital. This can cause kidney damage.
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Aileen Clarkson has been an award-winning editor and reporter for more than 20 years, earning three awards from the Society of Professional Journalists. She has worked for several newspapers, including "The Washington Post" and "The Charlotte Observer." Clarkson earned a Bachelor of Arts in journalism from the University of Florida.