Sunscreen preparations are evaluated according to their protection power against biological effects of ultraviolet radiation. UV-induced phenomena found on protected skin are compared with those on unprotected skin; thus the sunprotection factor is estimated. In order to assess the photoprotective power of sunscreens, only early UV-induced effects are decisive--such as erythema. PUVA erythema, pigmentation, activation of the ornithine decarboxylase, the influence on Langerhans cells, appearance of 'sunburn' cells, and changes of the DNA metabolism. We report on the various methods to obtain the specific sunprotection factors against UVB and UVA. Water-resistance, photostability, and pharmacokinetics depending on the vehicle are further criteria with regard to the evaluation of sunscreens. We rely on consumers information regarding the following properties of sunscreens: stickiness, oily shine, greasiness, discoloration, odor, and tolerance.