Food crops are easily to be contaminated by aflatoxin B₁ (AFB₁), which is more commonly encountered and considered to have most toxicity among the types of aflatoxins. When AFB₁ is ingested by dairy cows in contaminated feed, undergoes liver biotransformation and is converted into aflatoxin M₁ (AFM₁), which is excreted in milk. Because of this, when contaminated cereal and dairy products are ingested together, people will face the simultaneous exposure risk of AFB₁ and AFM₁. Studies confirmed that there is an increasing awareness of the deleterious effects of aflatoxins during their fate within the gastrointestinal tract (GIT). This study employed ICR (CD-1) mice (aged 4 wk) to investigate the combined intestine toxicity effects of AFB₁ and AFM₁. After acclimation, the mice were randomized into 4 groups of 10 each and received an oral administration of 0.5 mg/kg of BW AFB₁, 3.5 mg/kg of BW AFM₁, mixture of AFB₁ and AFM₁ (0.5 mg/kg of BW AFB₁, 3.5 mg/kg of BW AFM₁) and vehicle for 4 weeks (once a day), then blood and intestine were collected. The concentration of diamine oxidase (DAO), citrulline (Cit), intestinal fatty acid binding protein (I-FABP), d-lactate in serum and histomorphology, apoptosis analysis of duodenum, jejunum and ileum were measured. Statistical analysis was carried out by SAS 9.4 software. The results showed individual or combination of AFB₁ and AFM₁ did not affect body weight of mice significantly. And individual of AFB₁ or AFM₁ did not affect the concentration of Cit, I-FABP, and d-lactate in serum, but combined of AFB₁ and AFM₁ increased the DAO, I-FABP, and d-lactate in serum significantly. Individual of AFB₁ or AFM₁ increased the apoptosis ratio of cells in duodenum, jejunum, and ileum slightly, but combined of AFB₁ and AFM₁ increased it significantly. These results demonstrated that compared with individual of AFB₁ or AFM₁, combined of AFB₁ and AFM₁ could increase intestinal mucosa permeability and induce apoptosis of intestinal cells, which could provide basic information for further study of the combined intestinal toxicity effects of AFB₁ and AFM₁.