Skin exposure to solar ultraviolet radiation and pollutants causes several skin disorders, calling for protection methods such as sunscreen application. However, common sunscreen contains chemicals that have displayed toxicity when exposed to ultraviolet radiation. Therefore, alternatives approaches have been recently developed, such as the use of natural phytochemicals as active ingredients in photoprotection preparations. Here, we review skin protection with focus on the physics of ultraviolet radiation and photoprotection by ultraviolet filters. We present sensors for measuring ultraviolet radiation and ultraviolet radiation in ecosystems. We discuss the phototoxicity of drugs, preservatives, personal care products, and pollutants. Photocarcinogenesis, photoallergy, photostability, and toxicity of sunscreen ingredients and their impacts on human health and skin, are also reviewed. We observed that phytochemicals are promising for photoprotection due to their ability to absorb photon energy, and thus act as antioxidants.