Abstract—The experiment was conducted to investigate the effects of Liquid Methionine (LMA) and capsaicin in broiler. In the first study, an in vitro study was conducted investigating the antimicrobial efficacy of the combination between LMA and capsaicin against clinical isolates and reference laboratory strains of Escherichia coli ATCC25922. The minimum inhibitory concentration for Escherichia coli ATCC25922 was 0.125 %. The second study, a total of 192 commercial male broiler chicks was used. Birds were raised for 38 days in high ambient temperature and relative humidity in an open house. The chicks were divided into 2 groups in 6 replications with 16 chicks each in a completely randomized design for study the effects of supplementation of LMA 0.05% and capsaicin 2.5 ppm supplementation in diets on growth and intestinal morphology of broiler reared in open housed condition. The results indicated that broilers fed with LMA combination capsaicin, had higher final average daily gain (g) (P<0.05). However, the dietary treatments not influenced the feed intake, body weight and intestinal morphology (P>0.05). Therefore, the concluded that supplementation with LMA and capsaicin lead to improve the growth performance in live body weight of broiler reared in open housed condition.