Make-up and nail polish reduce our ability to monitor you during surgery. While in surgery, you will have a probe placed on the end of your finger to read the oxygen level in your blood. This probe cannot read through artificial nails or nail polish. If your oxygen levels drop, your fingernails would turn blue, but this would be hidden by your nail polish. Face makeup also can conceal your true skin color, which is an easy signal on how your body is reacting to surgery and if we need to put tape on your face or body, it may not stick to the make-up or cream on your skin. Almost all perfumes contain alcohol. During surgery, surgeons often use cauterization equipment and other electric or electronic devices that may give a spark and could catch fire. If alcohol-based perfume was on the skin, the fire would spread across the skin, causing widespread burns.