A wide range of phytobiotic feed additives are available on the market claiming to have beneficial effects on the growth of the host animal and to promote the development of a balanced microflora. The present study investigated the effects of the phytobiotic-prebiotic mixture of curcumin, wheat germ, and chicory on the growth performance and on the intestinal microflora composition of weaning piglets. Post weaning diarrhea causes significant losses for the producers, most commonly it is prevented by feeding high doses of zinc oxide (ZnO). The effect of a phytobiotic-prebiotic feed additive (1 kg T-1) was compared to a positive control (3.1 kg T-1 ZnO) and to a negative control (no feed supplement) in an in vivo animal trial. There was no significant difference in the final body weight and average daily gain of the trial and positive control groups, and both groups showed significantly (P<0.05) better results than the negative control. The feed conversion ratio of the phytobiotic-prebiotic supplemented group was significantly improved (P<0.05) compared to both controls. Both phytobiotic-prebiotic mixture and ZnO were able to significantly reduce (P<0.05) the amount of coliforms after weaning, even though ZnO reduced the amount of coliforms more efficiently than the trial feed additive, it also reduced the amount of potentially beneficial bacteria. Metagenomic data also corroborated the above conclusion. In the trial and positive control groups, the relative abundance of Enterobacteriaceae decreased by 85 and 88% between 3 weeks and 6 weeks of age, while in the negative control group a slight increase occurred. Lactobacillaceae were more abundant in the trial group (29.98%) than in the positive (8.67%) or in the negative (22.45%) control groups at 6 weeks of age. In summary, this study demonstrated that a phytobiotic-prebiotic feed additive may be a real alternative to ZnO for the prevention of post weaning diarrhea and promote the development of a balanced gut system.