Thieves oil is a proprietary oil blend of rosemary, cloves, lemon, cinnamon and eucalyptus used for cleansing and supporting a healthy immune system, according to the Young Living website. The name comes from stories about four thieves in France who covered themselves with spices to rob plague victims.
D. Gary Young developed Thieves oil after many years of historical and scientific research. The oil blend is a key ingredient in many products, such as toothpaste, mouthwash, household cleaner, spray, wipes and lozenges. A few drops the oil swallowed with water helps support the immune system. When a few drops of the oil blend are added to dishwater or used with a dishwasher, it thoroughly cleans dishes and eliminates odors, according to the Young Living website.