Fresh Breath Chewables are a natural hard chew infused with plant-based ingredients that promote oral health. Oil of oregano is an essential oil with natural antimicrobial properties. This powerful oil can delay the build-up of plaques on teeth, which lead to bad breath. Peppermint is a refreshing, aromatic herb that has traditionally been used by humans to freshen breath. An important component of most plants, chlorophyll can help reduce mouth odors.