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Already at the end of the 18th century, attempts were made to administer drugs transdermally. Several techniques were applied, including rubbing drug substances into the intact or wounded skin. Penetration enhancers were investigated as well, including human and animal body fluids, in particular gastric juice and saliva. In the 19th century, lipophilic solubilizers like chloroform and ether were tried. Although the experiments were mostly done against a pre-rational background some may be worth to be judged under scientific premises.