Background and Aim: Natural feed additives are important for broiler sustainability during the post-antibiotic era. This study aimed to evaluate the possible effects of the dietary supplementation of Lactobacillus casei-fermented mixture of red rice and aromatic ginger (FERMIX) on growth, blood profiles, intestinal bacterial content, and morphological measurements of broilers. Materials and Methods: Two hundred broiler chicks were allotted to four groups with five replications, including CONTROL (chicks provided with basal feed), FERMIX025 (basal feed supplemented with 0.25% FERMIX), FERMIX050 (0.50% FERMlX), and FERMIX100 (1.00% FERMIX). FERMIX is an anaerobic fermentation product from a mixture of red rice flour and aromatic ginger using L. casei. Blood, organs, digesta, and carcass were collected on day 35. Results: Final body weight, weight gain, feed intake, and feed conversion ratio did not differ (p 0.05) across treatments. FERMIX at 0.5% increased (p Conclusion: Although it did not influence growth, dietary FERMIX, especially at 0.5%, improved immune competencies, physiological conditions, and health of broilers' intestine. Keywords: broiler, fermentation, health, phytogenic, prebiotic, probiotic.