Picking your nose increases the risk of dementia.
Scientists have found that the bad habit is "a significant risk factor" for the brain disease as germs are transferred from the fingers to the nose where they travel up to the brain and cause inflammation.
Nose picking can also damage the nasal wall and make it easier for microbes to enter the bloodstream - triggering infections and inflammation.
However, the experts admitted that the amount of information on the issue was "scarce".
In a letter published in the American Journal of the Medical Sciences, they said: "Several pathogens, including those that invade the brain via the nasal epithelium... have been linked to Alzheimer's disease and have been isolated during post-mortem analysis.
"In conclusion, these studies show that nose picking is a significant risk factor and has a part in the progression of Alzheimer's disease.
"We propose more investigation to understand the association of nose picking with Alzheimer's disease in the form of case-control studies with larger sample populations."