The current study was carried out to evaluate the effect of oral administration of milk thistle extract (MTE) as a natural additive on the growth performance, nutrient digestion coefficients, and some blood parameters of growing goats. Twelve male goats aging about four months with an average initial live body weight of 19.04 kg were used in this experiment. Goats were randomly divided into four experimental groups (3 goats each). Experimental animals of each group were kept in a separate shaded pen and adapted for the tested rations for 14 days before starting the trial. Animals were weighed every seven days in the morning before offering feed and water. The growth trial lasted for 120 days. In the last week of the growth experiment, a digestibility trial was carried out in which feces and blood samples were collected. Adding MTE at 10, 20, 30 g/head (G₂, G₃, and G₄) showed a significant (P<0.05) improvement in final body weight, total body gain, ADG, and FCR when compared to the control group (G₁). Moreover, adding 20 g of MTE/head/day (G₃) showed the best significant (P<0.05) values. The digestion of OM, CP, EE as well as the TDN and DCP values were improved significantly (P<0.05) in goats fed diets with MTE addition (G₂, G₃, and G₄) compared with the control group (G₁). There were no significant differences (P>0.05) among the three levels of MTE addition (G₂, G₃ and G₄) except for the OM digestibility and TDN values, where adding 20 g of MTE/head/day (G₃) showed the best significant value (P<0.05). Results also showed that adding MTE (G₂, G₃, and G₄) made a significant (P<0.05) enhancement in glucose values when compared to the control group (G₁). Moreover, adding the MTE at 20 g/head/day (G₃) showed the best significant (P<0.05) value of blood glucose when compared to the other two levels of MTE addition (G₂ and G₄) and the control group (G₁). Total protein, urea, and creatinine values were significantly (P<0.05) increased, but, ALT and AST values were (P<0.05) decreased by MTE addition (G₂; G₃; and G₄) compared to the control group (G₁), with no significant differences (P>0.05) between the three levels of MTE addition (G₂, G₃ and G₄). Finally, we concluded that MTE addition as a natural health-beneficial additive to a high-concentrate diet in growing Shami goats might cause changes in blood chemistry that could enhance growth performance and nutrient digestion coefficients. Also, we found that the best MTE addition level was 20 g/head/day (G₃).