Sunscreens are agents that attenuate the effects of ultraviolet radiation on the skin by absorption or reflection of part of the incident radiation or by interception of harmful products of its interaction with the Sunscreens may be applied topically or ingested; however, topical agents are by far the more common and effective and only they will be discussed in this report. Topical sunscreens are formulated as creams or lotions and are characterized by their sun protection factor, a measure of their efficacy against sunburning and their substantivity, their resistance against removal after application.