The study was carried out to investigate the effects of by-products of herbal medicines on performance, enteric microflora and blood biochemical profiles and immunological parameters in broiler chicks. A total of ninety-six, 3-d-old birds were assigned to a basal diet (CON) or a basal diet supplemented with 0.15 % (HM1), 0.3% (HM2) or 0.5% (HM3) by-products of herbal medicines. There was a significantly (p<0.05) improved feed conversion ratio (FCR) in birds fed diet supplemented with 0.15% by-products of herbal medicines (HM1) compared with the control birds during starter period (3∼21 days). However, no difference in body weight, feed intake, total gain and FCR among treatment groups was observed during the entire feeding period (3∼35 days). The colony forming units (CFU) of E. coli and Lactobacilli in the digesta of ileo-cecum was not also affected by dietary treatment. Serum AST (aspartate aminotransferase) and glucose decreased (p<0.05) in birds fed diets supplemented with herbal medicines compared with those fed the basal diet. In particular, the birds fed diets supplemented with herbal medicines showed a significant (p<0.05) increase in blood mean corpuscular volume (MCV) level compared with the control birds. However, the most of blood biochemical and hematological parameters and immunoglobulins (IgG and IgA) were not affected by the dietary treatment. In conclusion, the low level of dietary herbal medicines showed beneficial effects on FCR during starter period and liver functions, suggesting that by-products of herbal medicines may be applicable as functional feed additives in birds.( (Huyghebaert et al., 2011;Jang et al., 2007;Lee et al., 2011;Wenk, 2000 (Gallois et al., 2009;Ilsley et al., 2005;Jang et al., 2013;Kang et al. 2010;Olas et al., 2003). 최근 면역증강제 로서 가장 주목을 받고 있는 것은 β-glucan으로 대식세포를 활성화시키는 작용과 면역세포의 수용체가 β-glucan을 인식 하여 대식세포의 면역작용을 증가시킨다 (Cox et al. 2010).한방생약물질로서 감초, 구기자 등은 면역증강, 해독작용, 간 기능증진, 콜레스테롤 저하, 항산화 작용 등과 같은 다양 한 약리작용이 보고되었다 (Kim et al., 2015;Lee and Ha, 1994;Vaya et al., 1997 (Table 5).육계 혈액의 적혈구 조성 (Table 6) 및 백혈구 감별계수(상 대적 %, differential counts)를 조사한 결과 (Table 7)