The great interest aroused during these last years by campaigns against intestinal parasites has naturally led to the use of various vermifuges. The experiments with each new drug have aroused high hopes, but the end results have been disappointing, for the free use of each drug has always been followed by the appearance of more or less numerous cases of intoxication. The work of Darling, Barber, and Hacker, and also the sanitary campaigns undertaken in the interior of the state of São Paulo, Brazil, have demonstrated the advantages of chenopodium oil over thymol and betanaphthol. Until that time these latter drugs enjoyed great popularity, but subsequently they have been used less and less, whereas chenopodium has generally taken their place. Chenopodium oil has been our best therapeutic weapon against uncinariasis on account of its high anthelmintic power, and despite its toxicity.