Head lice are caused by the host-specific, ectoparasitic insect Pediculus humanus capitis De Geer and remain a common human infestation. As a response to increasing resistance of head lice to present insecticidal agents, additional agents must be pursued. Inasmuch as nicotine has been used for controlling poultry lice, an in vitro study assessing its possible usage for human head lice was performed. Nicotine proved not to be an efficient insecticide, although it may facilitate removal of adult lice because it induces muscle twitches that may affect the insect's normal grip on hair follicles.