Mees' lines, or transverse striate leukonychia, are classically associated with arsenic poisoning, but have been described in other cases of acute or chronic illness. Their pathogenesis is thought to be a disruption of nail plate keratinization secondary to systemic stress. Mees' lines are observed in a patient with helminthic and amebic infections and no history of arsenic exposure. This case demonstrates another clinical setting in which Mees' lines can appear, providing further evidence that Mees' lines may chronicle systemic disease.