Abstract: The effects of Chinese Herbal Medicine Additives (CHMD) supplemented diets on weaned piglets growth performance, incidence of diarrhea, visceral organ mass, digesta pH, luminal microbial population and small intestinal morphology were studied in a 3 weeks trial. Total of 144 crossbred (Duroc x Landrace x Yorkshire) weaning piglets (BW = 5.86±0.24 kg) from 18 L with an age of 21 days were selected and divided randomly into 4 groups balanced for sex, weight and litter origin. In each group, the piglets were divided randomly into 3 pens (replicates, 12 pigs per pen), a corn-soybean meal-expanded soybean basal diet without antibiotics or probiotics was used as control and the other 3 groups were fed the control diet supplemented with the CHMD at rations of 0.5, 1 and 1.5% (wt/wt). In the 3 weeks trial, the data showed that. Compared to the control group, supplementation with 1% CHMD increased (p<0.01) Final Body Weight (FBW), Average Daily Weight Gain (ADWG) (p<0.01), Average Daily Feed Intake (ADFI) (p<0.05) and lower (p<0.01) F/G (total feed consumed (kg) by per kg gain in weight). Piglets fed the diet containing 1.5% CHMD had greater (p<0.05) ADWG, greater (p>0.05) ADFI, compared to the control group but without affecting F/G (p>0.05). There were no differences in ADFI, ADWG and F/G between the 0.5% CHMD group and the control group (p>0.05). Piglets fed the diet containing 1% CHMD and 1.5% CHMD both had lower (p<0.01) rate of diarrhoea, lower (p<0.01) incidence of diarrhoea and lower (p<0.01) index of diarrhoea compared to the control group. Piglets fed the diet containing 0.5% CHMD had lower (p<0.01) incidence of diarrhoea and lower (p>0.05) index of diarrhoea compared to the control group. Compared to the control group, piglets fed the diet containing 1% CHMD had higher (p<0.01) stomach weight and longer (p>0.05) small intestine, the 0.5% CHMD group and the 1.5% CHMD group both had no effect (p>0.05) on stomach weight and small intestine length. Compared to the control group, the 1% CHMD group and 1.5% both reduced the digesta pH of stomach (p>0.05), the 1% CHMD group reduced the digesta pH of duodenum (p>0.05), the 1% CHMD group and 1.5% both reduced the digesta pH of jejunum (p>0.05), the 1% CHMD group and 1.5% both reduced the digesta pH of ileum (p>0.05). Compared to the control group, the 1% CHMD group had a higher cecal and colonic lactobacilli count (p<0.01), a lower cecal and colonic Escherichia coli count (p>0.05) and had a higher LAB: E. coli ratio in the middle caecum (p<0.01), in the middle colon (p>0.05), pigs fed the diets with 1.5% CHMD had a higher cecal and colonic lactobacilli count (p>0.05) and had a higher LAB: E. coli ratio in the middle caecum (p>0.05). Compared to the control group, diets with 1% CHMD resulted in a greater VH in the duodenum (p<0.01), in the jejunum (p<0.01) and in the ileum (p>0.05), a lower CD in the duodenum (p<0.01), in the jejunum (p<0.01) and in the ileum (p>0.05), a greater (p<0.01) calculated VH:CD ratio in the duodenum in the jejunum and in the ileum, diets with 1.5% CHMD resulted in a greater (p>0.05) VH, a lower (p>0.05) CD and a greater VH:CD ratio (p>0.05) in the duodenum. The results show that the CHMD used in this study as a dietary additive could enhance indicators of gastrointestinal health, improve growth performance in weaned piglets, additionaly imply that the dose of 1% CHMD supplement is the most ideal concentration to achieve the most beneficial effects.