A multicentre field study was performed at 17 different locations in Germany to test a combination preparation with the active ingredients febantel (15 mg/ml) and pyrantel embonate (14.4 mg/ml) - marketed in Germany under the trade name Welpan (Bayer Vital) - for efficacy and tolerability against Toxocara canis, Ancylostoma caninum, Uncinaria stenocephala and/or Trichuris vulpis. The success of the treatment was compared with that of the active ingredient pyrantel embonate on its own. 420 puppies and young dogs of various breeds and with ages of up to one year were entered in the study following positive coprological testing for at least one type of nematode. 212 dogs were randomly allocated to treatment group I (febantel + pyrantel embonate)(1)) and 208 animals to treatment group II (pyrantel embonate). Both preparations were provided in the form of suspensions and were administered orally at a dosage of 1 ml/kg body weight (day )). The nematode eggs were counted before treatment (day 7-0) and once after treatment (day 5-12) using the modified McMaster-method. Cases where Trichuris vulpis was detected before treatment underwent a second follow-up examination on days 14, 15 or 16. Infection with Toxocara canis was diagnosed in 88.1 %, infection with hookworms in 35 % and infection with Trichuris vulpis in 3.3 % of the cases. 74.7 % of the animals were infected with only one type of nematode, 24.1 % with two and 1.2 % with all three nematode types. Following one single treatment with the combination of febantel + pyrantel embonate, a 97.2 % reduction of the Toxocara canis eggs was observed, while treatment with pyrantel embonate only reduced the egg count by 83.7 %. The reduction in hookworm eggs following treatment with the combination product was 96.8 %, but only 65.2 % after treatment with the single substance. The reduction of Trichuris vulpis eggs was 85.4 % following treatment with febantel + pyrantel embonate (group I: 8 animals) and 13.9 % after treatment with pyrantel embonate (group II: 6 animals); however, the low number of subject animals must be taken into account. The reduction in egg counts of Toxocara canis, hookworm and Trichuris vulpis was statistically significantly (p < 0.01) higher following treatment of the dogs with the combination of febantel + pyrantel embonate than after treatment with pyrantel embonate alone. Both preparations were well tolerated by the puppies and young dogs.