Lapachol is a naphthoquinone that was first isolated by E. Paterno from Tabebuia avellanedae (Bignoniaceae) in 1882. A wide spectrum of therapeutic activities have been attributed to lapachol or its derivatives viz., anti-abscess, anti-ulcer, antileishmanial, anticarcinomic, antiedemic, anti-inflammatory, antimalarial, antiseptic, antitumor, antiviral, bactericidal, fungicidal, insectifugal, pesticidal, protisticidal, respiradepressant, schistosomicidal, termiticidal, and viricidal. Originally isolated from species of the Bignoniaceae family, lapachol can also be found in other families such as Verbenaceae, Proteaceae, Leguminosae, Sapotaceae, Scrophulariaceae, and Malvaceae. The interesting and most usefull knowledge on lapachol, which is reviewed in this paper, can be used as a starting point in future research endeavors.