This research was performed to investigate the effects of milk thistle (MT), toxin binder (TB) and marine algae (Spirulina platensis; SP) on the performance, blood indices, humoral immunity and cecal microbiota of broiler chickens exposed to aflatoxin-B1 (AFB1). A total of 300 one-day-old male chicks were equally divided into five treatments, with six replicates with 10 birds per treatment. Dietary treatments included: (T1) a control diet (without any feed additive or AFB1); (T2) control diet + 0.6 mg AFB1/kg; (T3) T2 + 10 g/kg MT; (T4) T2 + 1 g/kg TB; and (T5) T2 + 10 g/kg SP. BWG and FI were found to be considerably reduced in broilers given AFB1-contaminated diets (p < 0.05). The FCR was negatively influenced in birds fed AFB1-contaminated diets (p < 0.05). MT, TB, and SP powders also reduced the deleterious effects of AFB1 on the growth of chickens (p < 0.05). In comparison with the control birds and the other treatments, broilers given AFB1-contaminated diets had a higher relative weight of abdominal fat (p < 0.05). The feeding of AFB1 resulted in a substantial rise in AST and ALT activity (p < 0.05). MT, TB, and SP powders significantly decreased blood AST and ALT activity in broilers (p < 0.05). The AFB1 and MT groups had the lowest skin thickness (p < 0.05) twenty-four hours after injection. The phytohemagglutinin injection results showed that the TB and SP were more efficient than the other additives in removing toxins from the feed sources (p < 0.05). The antibody titer against sheep red blood cells (SRBCs) was lower in the AFB1 group compared to the control group at 28 days of age (p < 0.05). When comparing AFB1-fed chicks to the control treatment, there was a significant (p < 0.05) concentration of cecal Coliform bacteria. When MT, TB, and SP powders were added to AFB1-contaminated diet, cecal Coliforms were decreased (p < 0.05). When fed AFB1-contaminated diets, it can be concluded that MT, TB, and SP are suitable for supporting growth performance, immunological function, and the serum biochemical parameters of broiler chickens.