Blood cultures are the gold standard for the etiological diagnosis of bacteremia, though false-positive results are relatively frequent primarily due to contamination from skin flora during sample extraction. Correct skin antisepsis is important for reducing the bacterial load and opportunities for contamination. However, there is currently no solid consensus on the best antiseptic method. Alcohol has a potent immediate bactericidal effect, and there is some scientific evidence in favor of its combination with chlorhexidine, but most studies on this issue are heterogeneous and with inconclusive results. Some authors even suggest that the chosen antiseptic is irrelevant to the contamination rate, provided the blood culture extraction method is adequate and is performed by a trained professional. This article is part of a supplement entitled "Antisepsis in the critical patient", which is sponsored by Becton Dickinson.