Conventional reed diffusers, even if they are created with essential oils, typically use a solvent base of dipropylene glycol. This is the same ingredient that is considered the “less-toxic” ingredient in antifreeze. Some also contain petrochemical derived or SD 40 alcohol. They often contain phthalates – a known hormone disrupter in the human endocrine system. rareESSENCE Reed Diffusers contain an innovative base of unique essential oils that help our aromatherapy essential oil blend flow up the reeds and disperse into the air. There are no toxins or chemical bases in our products whatsoever.