The objective of this study was to determine the effects of 2 different adsorbents composed of yeast fractions and bentonite in different proportions (AD1 and AD2) during an aflatoxin (AF) challenge. Lactating Holstein cows [(n = 76); BW (mean ± SD) = 698 ± 72 kg; DIM = 153 ± 83 d] were assigned to 1 of 5 treatments in a randomized complete block design. Period was 28 d with measurement phase on d 22 to 28. From d 22 to 24, cows received an AF challenge (100 μg of AFB₁/kg of diet DM administered orally). The appearance and disappearance of AF excreted in milk was tested at each milking from d 22 to 28 using SNAP tests (SNP; IDEXX, Inc.). Blood was sampled on d 1, 22, and 26 (n = 3 per cow) of wk 1 and 4 for each period and analyzed for superoxide dismutase (SOD) content. Milk samples from d 22 to 26 were analyzed for AFM₁ concentrations by HPLC. Treatments were: control (CON), no AD or AF; positive control (POS), no AD plus AF challenge; 30 g per cow per day of AD1 30 and AF challenge (AD30); 60 g per cow per day of AD1 60 and AF challenge (AD60); and 60 g per cow per day of AD2 and AF challenge. Statistical analysis was performed using the MIXED procedure of SAS. Cows in CON had no positive SNP tests, while cows in POS had 7.85 ± 0.27 positive SNP tests (P < 0.001). Plasma SOD concentrations were greater for POS than CON at 2.77 and 1.96 ± 0.05 U/mL, respectively (P < 0.001). A quadratic treatment effect was observed for plasma SOD concentrations at 2.77, 1.99, and 1.97 ± 0.05 U/mL for POS, AD30, and AD60 treatments, respectively. Aflatoxin M₁ transfer (1.14 and 0.00 ± 0.16%), excretion (29.52 and 0.00 ± 4.58 µg/d), and concentrations in milk (0.76 and 0.00 ± 0.16 µg/kg) were greater for the POS treatment than the CON, respectively (P < 0.0001) but no differences were observed among other treatments. Oral supplementation of yeast and bentonite clay based AD during AF challenge resulted in quadratic changes in plasma SOD, and fecal AFB₁ concentrations. In conclusion, yeast cell wall and bentonite based AD may be beneficial in reducing inflammation during AF challenge.