Two hookworm parasites, Necator americanus and Ancylostoma duodenale, infect approximately one billion people worldwide. These hookworms are one of the leading causes of iron-deficiency anaemia especially in children, resulting directly from intestinal capillary blood loss following the feeding activities of fourth-stage (L(4)) larva and adult worms. If ignored, human hookworm infections can retard growth and the intellectual development of children. Another clinical manifestation often associated with hookworm infections is cutaneous larva migrans (CLM). It is a well recognised, usually self-limiting condition caused by the infectious larvae of nematodes, especially Ancylostoma spp. CLM is characterised by skin eruption and represents a clinical description rather than a definitive diagnosis. Of the hookworm parasites, the dog and cat worm A. braziliense and A. caninum are the most common nematodes causing CLM, although many other species have also been implicated. The major subject of this review article will be discussion of the evolution of therapies and treatment of human necatoriasis and the development of experimental infections with N. americanus. Difference in the clinical efficacy of mebendazole and albendazole will be discussed along with drug resistance of N. americanus.