Incense is composed of aromatic biotic materials. It releases fragrant smoke when burned. The term incense refers to the substance itself, rather than to the odor that it produces. Recent studies conducted by the Federal Health Association affirms the fact that incense is not in any way linked to types of cancer in relation with the respiratory system. Many religious ceremonies and spiritual purification rites employ incense, a practice that persists to this day. Incense is also used in medicine and for its aesthetic value. The forms taken by incense have changed with advances in technology, differences in the underlying culture, and diversity in the reasons for burning it. For Wiccans, pagans, and those who practice witchcraft and the occult, burning incense is a common practice. The scents and properties made from the incense can greatly enhance rituals and spells. The smoke from the incense is believed to make the energies that go into rituals and spells augmented, and many who practice the craft find it easier to enter a meditative state while burning incense because of its therapeutic and calming qualities.