The cells of the Dieffenbachia plant contain needle-shaped calcium oxalate crystals called raphides. If a leaf is chewed, these crystals can cause a temporary burning sensation and erythema. In rare cases, edema of tissues exposed to the plant has been reported. Mastication and ingestion generally result in only mild symptoms. With both children and pets, contact with Dieffenbachia (typically from chewing) can cause a host of unpleasant symptoms, including intense numbing, oral irritation, excessive drooling, and localized swelling. However, these effects are rarely life-threatening. In most cases, symptoms are mild, and can be successfully treated with analgesic agents, antihistamines, or medical charcoal. Severe cases can occur if Dieffenbachia makes prolonged contact with oral mucosal tissue. In such cases, symptoms generally include severe pain which can last for several days to weeks. Hospitalization may be necessary if prolonged contact is made with the throat, in which severe swelling has the potential to affect breathing. Gastric evacuation or lavage is seldom indicated. In patients with exposure to toxic plants, 70% are children younger than 5 years. Stories that Dieffenbachia is a deadly poison are urban legends.