Publisher Summary This chapter provides an overview of Antifungal drugs. In comparison with bacteria or viruses, fungi are more complex organisms. They have ribosomes, cellular membrane components, and a nuclear membrane. Therefore, antibacterial antibiotics are, as a rule, ineffective against pathogenic fungi. Fungal infections (mycoses) occurs less than bacterial or viral infections. The most widespread are dermatophytic fungal infections, which include skin, hair, and nails. Most infections can be cured by using topical drugs such as tolnaftate, undecylenic acid, haloprogin, clotrimazole, and miconazole. Griseofulvin is used orally for deep infections, in particular for infections of the nail bed. Antifungal drugs can be divided into polyenes, imidazole, and triazole derivatives, allylamines, and others. The polyenes (nystatin, amphotericin B, natamycin) bind with sterols in the fungal cell wall, principally ergosterol. This causes the cell's contents to leak out and the cell dies. Imidazole derivatives such as ketoconazole, miconazole, clotrimazole, econazole, butoconazole selectively raise the permeability of the membrane of fungal cells by interfering with the biosynthesis of sterins, in particular ergosterin, by inhibiting its synthesis and by changing the lipid content of the membrane. The chapter focuses on specific examples of these classifications, highlighting their chemical structure and action mechanism..