The Authors describe and analyse the antihelminthic activity of the association piperazine hexahidrate and thiabendazole The study was carried on 41 subjects parasitei by Ancylostomidae plus Áscaris lumbricoides and/or Strongiloides stercoralis. By using a schedule of 5 ml/15 kg, twice a day, during 3 consecutioe days, they found 26 (63.4%) of cures. Considering each parasite separately they found: Ascaris, 16 cures in 18 subjects (90% of cures); S. stercoralis, 30 cures in 31 subjects (97%); Ancylostomidae, 27 in 41 sujects (65.8%). The Authors consider the associalion as an efficient agent in treatment of individual cases as well as in the prophylaxy of the human helminthiasis