Known medically as "rhinotillexomania," nose-picking is not only an unsightly and unsanitary habit, it also poses as a health risk.
A multitude of bacteria can live just on the tip of our fingers, literally. The microbes also love to hide underneath fingernails, whether or not they appear to look clean. Thus, when the finger is introduced to the nasal passage, bacteria can get into your system. Most notably, the Staphylococcus aureus bacteria is commonly carried from the finger to the nose. A drug-resistant strain of this bacteria, MRSA, is notorious for wreaking havoc on the body's immune system.
Another health concern from nose-picking? Our finger nails can tear the skin in the nasal passages, causing nosebleeds. These events also increase the risk for more serious infections, as bacteria in the nose can easily slip into the blood stream and cause more severe infections.
Researchers have acknowledged that this socially unacceptable habit is hard to kick, since we usually pick it up in early childhood. However, given the health risks, perhaps it would be more prudent (and more sanitary) to reach for a Kleenex next time.