Diethylstilbestrol (DES), together with dienestrol and hexestrol belongs to the group of stilbenes. Increased weight gain and improved feed conversion after administration of DES has been observed in cattle, chicken and lambs. However, in the EC the use of anabolics has been banned, and especially DES has been banned in all countries due to its carcinogenic properties. The DES-EIA can be used for the screening of biological samples for the presence of the following stilbenes (% of cross-reactivity): diethylstilbestrol (100%), hexestrol (25%) and dienestrol (15%). The DES-EIA shows no cross-reactivity (< 0.1%) for zeranol, 19-nortestosterone, progesterone, cortisol and testosterone. Detection limits as low as 0.5 ng/ml can be reached in urine samples.