The plant known variously as Moses in the Cradle, Boat Lily, or Oyster Plant (Tradescantia spathacea) is a common houseplant prized for its striking foliage, featuring deep green on the top surface and vibrant purple underneath. Despite its popularity, this plant is considered toxic to both humans and pets. The toxicity is primarily localized, causing irritation upon contact with the skin or mucous membranes and when ingested. Understanding the specific mechanism behind this irritation is important for any household that features this decorative plant.
The Specific Toxic Hazard
The danger posed by Tradescantia spathacea is not a chemical poison, but a physical irritant embedded within the plant’s structure. The plant contains high concentrations of microscopic, needle-shaped crystals composed of insoluble calcium oxalate. These crystalline structures are known as raphides, which are stored under pressure within specialized cells called idioblasts.
When any part of the plant—including the leaves, stems, or flowers—is chewed, cut, or crushed, the pressure is released, and these sharp crystals are forcefully ejected. This action causes mechanical irritation, piercing the delicate tissues of the skin, mouth, and digestive tract.
Recognizing Symptoms of Contact and Ingestion
Exposure to the plant’s sap results in two distinct sets of symptoms: dermal contact or ingestion. Dermal exposure, which often occurs when handling the plant during pruning or repotting, can lead to contact dermatitis. Symptoms of skin contact include an immediate stinging sensation, redness, and inflammation of the affected area. This localized irritation may progress to a burning feeling, itching, and the development of minor blisters or a rash.
Ingestion exposure, most common in small children or pets, produces an immediate and severe reaction within the mouth and throat. This results in intense burning pain in the lips, tongue, and oral cavity as the microscopic crystals embed themselves in the mucous membranes. Other symptoms include excessive drooling, difficulty swallowing (dysphagia), and localized swelling of the mouth and tongue. Significant swelling in the throat area could interfere with normal breathing, requiring immediate action. Gastrointestinal upset, such as nausea, vomiting, and abdominal discomfort, may also follow.
Immediate Action and Safety Measures
If contact with the plant’s sap occurs, the affected area should be immediately and thoroughly flushed with cool water and mild soap. Rinse the skin for several minutes to ensure all residual sap and crystals are removed. For accidental ingestion, remove any remaining plant material from the mouth and then rinse the mouth thoroughly with water.
To help soothe the burning sensation in the mouth and throat, give the individual small amounts of cold water or milk to drink. Never attempt to induce vomiting, as this can cause the irritating crystals to damage the esophagus a second time. Following any exposure, especially ingestion, contact the national Poison Help Line at 1-800-222-1222 immediately for expert advice.
Seek emergency medical attention without delay if any signs of a severe reaction occur, such as trouble breathing, a hoarse voice, or significant swelling of the lips or throat. To prevent future incidents, keep all Tradescantia spathacea plants out of reach of children and household pets. When handling or pruning the plant, wearing gloves and long sleeves is recommended to prevent sap from coming into direct contact with the skin.