Fungi are eukaryotic organisms that can live as parasites or saprobes. They cause infections called mycoses that can be superficial, like those caused by dermatophytes and Candida, or deep infections like candidiasis and aspergillosis. Antifungals target the cell membrane, cell wall, or DNA synthesis and work at the nuclear level like fluconazole or at the cell membrane level like azoles and allylamines. Drug interactions can increase or decrease serum drug concentrations by affecting absorption or metabolism. Antifungals are used for various fungal infections topically or systemically depending on the infection.