This means these have been carried with another essential oil so will not harm the skin. For oils with no carrier go to certififed essential oil section on our page. In most cases if your are applying directly to skin (exception being feet)this what your using oils in this section. Most company's choose not to make you aware you that can they can add another essential oil so you don't get skin irritations and its still a pure essential oil. We at Rainbow Sky choose to make you know the truth. For essential in the purest form go to our therapeutic oil section where you find some purest, strongest and finest oils on the market today..