Elephant Ear Sap Causes Painful Oxalic Acid Burns

The stinging sensation you felt after handling a yellowing elephant ear leaf is an oxalic acid burn. All members of the arum family—spathiphyllum, Jack-in-the-pulpit, caladium, elephant ear—contain oxalic acid crystals in their sap. These needle-like crystals penetrate skin and cause intense irritation.

While elephant ear roots are eaten as poi in Hawaii, they must be thoroughly cooked to neutralize the acid. One gardener suffered serious eye injury when sap squirted into her eye during pruning. Always wear gloves and eye protection when handling these plants.