This experiment was conducted to study the effects of acanthopanax senticosus (AS) extracts as dietary additive on digestion and absorption of protein or amino acids in weaned piglets. Sixty three-way crossbred piglets weaned at 21 days of age were randomly assigned to 3 treatment groups, representing supplementation with 0 or 1 g/kg of AS extracts, or 0.2 g/kg of colistin to maize- and soybean meal-based diets (n = 20 per group). Blood samples of 5 piglets per group were randomly collected on days 7, 14 and 28 after initiation of the addition to determine serum contents of free amino acids, then digesta at terminal ileum was collected to analyze the contents of amino acids after the sampled piglets were sacrificed. The results showed that the serum contents of amino acids in the extracts-supplemented group were gradually increased and digesta amino acid contents were gradually reduced at the same time as the experiment proceed when compared with the other 2 groups. These findings indicated that the AS extracts could enhance the ability of digestion and absorption of protein or amino acids, then improve the growth performance in weaned piglets.