The objective was to evaluate the efficacy of Toxy-Nil (TN) or Unike Plus (UP) in reducing aflatoxin (AF) M₁ concentrations in milk of dairy cows challenged with dietary AFB₁. Thirty-two mid-lactation Holstein cows were blocked by parity, days in milk and milk yield, and were randomly assigned within block to receive one of the following treatments: 1) 2.8 mg of AFB₁ /cow/day (positive control, PC); 2) 2.8 mg of AFB₁ + 100 g of TN/cow/day; 3) 2.8 mg of AFB₁ + 100 g of UP/cow/day; or 4) no AFB₁ and no adsorbents (negative control, NC). For 7 d, treatments were top-dressed twice daily and mixed into the top portion of the TMR diet immediately before each feeding using 150 g of sweet feed as carrier. After the experimental period, cows were fed the NC diet and clearance of AFM₁ via milk was monitored for 7 d. Feed and water were available ad libitum throughout the trial. Treatments had no effect on feed intake, milk yield, milk composition, or SCC (P ≥ 0.10). Relative intake of AFB₁ was similar (P ≥ 0.22) among PC, TN and UP, averaging 106.5, 107.6, and 102.5 ± 2.9 mg/kg of diet dry matter (DM), respectively. Relative intake of adsorbents was similar (P = 0.09) between TN and UP, averaging 0.38 and 0.37 ± 0.01% of diet DM, respectively. Concentration and mass of AFM₁ excreted in milk were similar (P ≥ 0.43) between TN and UP, but were lower (P < 0.001) than PC; concentrations averaged 0.2, 0.3 and 0.6 ± 0.1mg/kg, respectively, and excretion averaged 8.1, 9.8 and 20.5 ± 1.7 mg/d. Transfer of AF from feed to milk averaged 1.0, 1.3 and 2.7 ± 0.2% for TN, UP and PC, respectively. Treatments TN and UP both reduced AFM₁ in milk (63.4 and 53.5 ± 8.2%, respectively, P < 0.001) with similar efficacy (P = 0.40). The clearance rate of AFM₁ in milk did not differ (P ≥ 0.40) among PC, TN and UP (27.1, 27.4 and 28.9 ± 1.3%/d, respectively). Results indicate that inclusion of 100 g of TN or UP significantly reduced AFM₁ in milk of cows consuming TMR containing approximately 105 mg of AFB₁/kg of diet DM. Results also suggest that both TN and UP reduced absorption of AF.