We report here observations clearly demonstrating that gloves can have a deleterious impact on an IEF experiment. These observations were made during the practice of analyses for anti-doping control of erythropoietin. We show that the wearing of nitrile gloves to apply the catholyte strip onto the IEF gel may be responsible for dramatic distortions in the pattern of this hormone. These observations point out that gloves must not be considered only as protective items but also as possible factors in an analytic process.