The contamination of animal feed with mycotoxins is a worldwide problem in the animal husbandry, but it also represents a serious threat for the whole food chain. The health of both animals and humans is potentially endangered. From this point of view aflatoxins are a class of mycotoxins especially well known. Therefore, new strategies to combat these natural contaminants are constantly being developed. The most applied method to protect animals against aflatoxicosis is the utilization of feed additives aimed to adsorb aflatoxins. In order to estimate adsorbing potential of feed additive “MycoStop DUPLO”, designed for the prevention and/or alleviation of adverse effects of aflatoxin B1 in animal nutrition, in vitro trial was conducted. As a result of the experiment, conducted at pH 5 during 120 minutes of incubation at 37°C, the optimal formulation of the adsorbent was revealed. This product, in low concentration and in the presence of high amounts of toxin, met the stringent European regulation requirements for minimum 90% aflatoxin binding efficiency (90.1% achieved with 0.02% adsorbent and 4 mg/L toxin concentration). In higher adsorbent (0.2%), and lower toxin (0.2 mg/L) conditions, adsorption was 99.6%. Such outcome indicated the validity of in vitro experimental approach which can serve as a reliable fast tool for triage of adsorbents and preselect them for in vivo tests.