We investigated the antibacterial susceptibility of intestinal lactobacilli of Estonian and Swedish children aged 1-2 y. Sixty isolates (10 species) of lactobacilli (29 Estonian and 31 Swedish strains) were tested against ampicillin, cefuroxime, cefoxitin, gentamicin, ciprofloxacin, tetracycline, vancomycin, metronidazole and erythromycin. We observed that intestinal lactobacilli do not display uniform susceptibility to antibiotics. None of the tested lactobacilli was resistant to ampicillin, gentamicin and erythromycin. Single strains were resistant to cefuroxime and tetracycline, about half of the strains to cefoxitin and ciprofloxacin and 73% of the strains to vancomycin. All studied strains were resistant to metronidazole. Most of the strains investigated were resistant to two or three antibiotics out of nine. Some differences in susceptibility were noted between strains belonging to different fermentation types. No differences in susceptibility were found between Estonian and Swedish isolates. Metronidazole, cefoxitin, vancomycin and ciprofloxacin seem to be safer for gastrointestinal lactoflora than other tested antibiotics in both countries.