Anthelmintics, or Vermifuges, are medicinal substances employed to destroy and expel worms (entozoa) from the alimentary canal. Their action differs according to the nature of the substance used, either to destroy by a direct poisonous influence or by mechanical means. The most powerful of the cathartics (drastic) also acts as anthelmintics by the copious secretion and exhalation which they produce from the alimentary canal. When anthelmintics are employed, they must be persevered in for several days, with the occasional intervention of an active cathartic.

Belonging to this class are such agents as wormseed, spigelia, santonica, cowhage, male fern, oil of turpentine, kameela, pumpkin seed, kousso, calomel with gamboge, calomel with pink root, iron preparations, etc., etc.