A combination of organic acids OA (formic, propionic and acetic), phytochemical (PC) and permeabilizing substance (PS) which alters the permeability of the outer membrane in gram-negative bacteria, has shown synergistic effect on the inhibition of bacterial growth in vitro as well as improved growth performance in weaning pigs in vivo. The aim of the trial was to determine the efficacy of the combination of OA, PC and PS in the form of combined natural growth promoter (NGP) Biotronic Top3, at 3 different levels (0.1, 0.15, and 0.2%) on the growth performance of wean pigs. 600 pigs weaned at 28 d were assigned to 4 treatments: (1) basal diet, (2) basal diet combined with 0.1 NGP, (3) basal diet combined with 0.15 NGP and (4) basal diet combined with 0.2% NGP with 6 replicates by treatment. Starter diet from d 28 to d 56 (ME 14.00 MJ/kg, CP 17%, Met 0.45% and Lys 1.40%) and grower diet from d 56 to d 71 (ME 13.4 MJ/kg, CP 17.50%, Met 0.36% and Lys 1.20%) were fed. BW of the animals was recorded at d 28, 56 and 71. ADG and FCR were calculated. Dietary supplementation of NGP at inclusion levels of 0.1, 0.15 and 0.2% enhanced growth performance. The BW (kg) was improved on d 56 (quadratic P < 0.01; 17.2^a, 18.4^b, 18.7^b and 18.9^b for 0, 0.1, 0.15 and 0.2% of NPG, respectively) and d 71 (quadratic P < 0.01; 26.9^a, 28.1^b, 28.3^b, and 28.3^b for 0, 0.1, 0.15 and 0,2% of NPG, respectively) as well as feed intake (g/d) (quadratic P < 0.01; 762^a, 804^b, 816^c, and 818^c for 0, 0.1, 0.15 and 0.2% of NPG, respectively). ADG (g) (P < 0.1) was only numerically different among treatments (439, 458, 465, and 465 for 0, 0.1, 0.15, and 0.2% of NPG, respectively). There were no differences in FCR (P > 0.1). Diet supplemented 0.15% combined NGP had the highest final BW and ADG tended to be greater compared with other groups. The supplementation with the combined NGP at a level of 0.15% was most beneficial.