Even in small amounts, lemon peel is high in fiber and vitamin C. It also contains calcium, potassium and magnesium. Lemon peel has strong anti-bacterial properties and is thought to fight common oral disease that stem from bacteria. In addition, the D-limonene that gives lemons their citrus smell has been tested in people with gallstones. A whopping 48% who were given lemon peel had their gall stones dissolve avoiding the need for surgery.