A field trial is described for testing the acceptance of a new machine made bait (ALTROFOX/91) for oral immunization of red foxes. The investigations were undertaken in direct comparison with a bait with known attractiveness for foxes. After the choice of suitable field trial areas the baits were distributed at a density of 18/km2 by fixed-wing aircraft. Each bait version contained a different derivate of tetracycline as a biomarker. The evaluation of the attractiveness and acceptance by red foxes and non target species was established by visual controls on the third, seventh and 14th day after distribution and biomarker proving in bone specimens of investigated animals.