Sclerotherapy with foam is becoming increasingly popular for the treatment of varicose veins. There is no consensus on the necessity of sterile air or other gases to produce foam. To evaluate the potential risk of bacterial inoculation of polidocanol (POL) foam using room air and the antimicrobial properties of polidocanol. The amount of airborne microorganisms was quantitatively measured. Four bacterial strains were tested for susceptibility to polidocanol: Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Streptococcus pyogenes. Air measurements varied as a result of air movement and the number of people in the room. Although the risk of introducing one colony-formin unit can be calculated as less than 1 in 330, the clinical relevance is still to be determined. No inhibition of bacterial growth was achieved with POL in of any of the tested strains. Foam sclerotherapy with POL prepared in a standard treatment room is a safe procedure without the risk of introducing a severe bacterial complication. The use of sterile air, nitrogen, or carbon dioxide is unnecessary and will make foam sclerotherapy with POL more elaborate and more expensive to use.