In this study, antimicrobial activity of oriental herbal medicine extract (OHME) was tested for some organisms and the preventive effects of OHME for the colonization of Campylobacter jejuni on epithelium of small intestine were examined in Korean native broiler chickens fed a forage added 1.0% OHME. The isolated Campylobacter spp were biotyped, serotyped and the susceptiblility of isolates to antimicrobial agent were examined. The growth of Staphylococcus aureus was inhibited in 0.25% OHME. C. jejuni and C. coli were inhibited in 0.1% OHME, and Salmonella spp, Lactobacillus acidophilus and Escheichia coli 0157 were inhibited in 2.0% OHME. For the application of forage added 1.0% OHME in broiler chicken farm, the frequency of Campylobacter spp from feces, liver and spleen sample of chickens were examined during 2 weeks interval. The frequence of Campylobacter spp in feces from chickens fed assorted forage (control group) was increased from 25% in first week to 75% in seventh week. But the frequence of Campylobacter spp in feces sample from chickens 134 forage added OHME was slightly reduced from 25% in first week to 15% in seventh week. The frequence of Campylobacter spp in liver, and spleen was 13.7% and 10% respectively after seventh week in control group, but the Campylobacter spp was not isolated after fifth week in live and spleen from chickens fed forage added OHME. Isolated 56 strains of thermophilic Campyiobacter from Korean native chickens was classified as C. jejuni (76.7%), C. coli (214%) and C. laridis (1.6%). The majority of 43 isolates of C. jejuni was classified on biotype I (60.4%), II (30.2%). Most of 12 isolates of C.coli were biotype I (83.3%). Isolated 31 strains C. jejuni of showed 11 different serotype, and serotype 36 (18.6%), 17 (13.9%)were most frequent. Isolated 10 strains of C. coli showed 5 different serotypes and serotype 31 (33.3%) and 21 (25%) were relatively common. Isolated Campylobacter spp were highly susceptible to nalidixic acid, amikacin, gentamicin, colistin and chloramphenucol.