The authors present the resulls of the treatment of Ascaris, Trichuris and hookworm infection with an association of piperazine-thiabendazole and dimethilpolisiloxane; the cure rates were generally the achieved for ascariasis with dosis of piperazine of 60 mg/kg body weight for 3 days. 50% of the cases of hookworm infection cured after treatment; for whipworm infection the parasitological cure was very low - 26% (of 76 patients). Tolerance was good. An improvement in clinicai manifestations, specially abdominal pain, diarrhoea and obstipation was observed in most patients.