The author treated 40 patients infected with intestinal nematodes with a new salt of piperazine - Bis (2,4,5-Trichlorophenol) piperazine in a single dose of 50mgm/kg of body weight given at fasting or two hours after the first meal. Twenty-five patients (62,5%) infected by hookworm toere cured after a serie of treatment, and six patients (15%) were cured with a second course of the drug. A global cure rate of thirty-one cases (77,5%) was observed. The drug was well tolerated, and only two patients refered vomiting immediatly after ingestion of the drug. The author considers this neio compound very effective against hookworm infection.