420 patients were treated with a combination of mebendazol (5ml or one tablet equaling 100mg) and thiabendazole (various doses) given twice a day for two to three days. The following indexes of cure were obtained. Approximately 90-95% for Enterobius, Strongyloides, Tricocephalus and Ascaris and between 80-90% for hookworm. These results were in hospitalised patients with a control of cure of four examinations in a month. In outpatients the indices of cure declined related to the degree of vigilance observed in relation to drug taking. Then the dose of thiabendazole is raised to 166mg-250mg in 5ml or 500mg in a tablet the duration of treatment can be reduced to three or two days. However more side effects are observed with this regimen.