 The sap of most species of Vanilla orchid which exudes from cut stems or where beans are harvested can cause moderate to severe dermatitis if it comes in contact with bare skin.Washing the affected area with warm soapy water will effectively remove the sap in cases of accidental contact with the skin.The sap of vanilla orchids contains calcium oxalate crystals, which appear to be the main causative agent of contact dermatitis in vanilla plantation workers.