SINGLE OILS THAT ARE APPROVED FOR INTERNAL USE BY THE FDA

Basil, cinnamon, clove, coriander, dill, eucalyptus, fennel, frankincense, galbanum, geranium, ginger, grapefruit, jasmine, juniper, lavender, laurus nobilis, lemon, lemongrass, marjoram, melaleuca, mountain savory, myrrh, nutmeg, orange, oregano, patchouly, black pepper, peppermint, pettigrain, pine, rose, rosemary, sage, sandalwood, spearmint, spruce, tangerine, tarragon, thyme, valerian root, and ylang ylang. (ref.)