Ledol is a poisonous sesquiterpene that can cause cramps, paralysis, and delirium. Caucasian peasants used Rhododendron plants for these effects in shamanistic rituals. Ledol is a poisonous sesquiterpene that can cause cramps, paralysis, and delirium. Caucasian peasants used Rhododendron plants for these effects in shamanistic rituals. Ledol is found in labrador tea, an herbal tea (not a true tea) made from three closely related species: Ledol is also found in the essential oil of priprioca at a concentration of around 4%. Ledol is also found to varying concentrations in the following plants: