Calcium oxalate crystal-containing plants

B. Group 2a plants contain insoluble calcium oxalate crystals that may cause burning pain and swelling of mucous membranes. Many houseplants are commonly found in this category. 

C. Group 2b plants contain soluble oxalate salts (sodium or potassium) that can produce acute hypocalcemia, renal injury, and other organ damage secondary to precipitation of calcium oxalate crystals in various organs (see p 295). Mucous membrane irritation is rare, allowing patients to ingest sufficient quantities to cause systemic toxicity. Gastroenteritis may also occur. 

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