Molecules found on mobile phones reveal an astonishing amount about the owner's health and lifestyle - including their food preferences and medication.
Californian scientists found traces of everything from caffeine and spices to skin creams and anti-depressants on 40 phones they tested.
We leave traces of molecules, chemicals and bacteria on everything we touch.
Even washing hands thoroughly would not prevent the transfer to everyday objects, the researchers said.
Using a technique called mass spectrometry, the University of California San Diego research team tested 500 samples taken from 40 adults' mobile phones and hands.
They then compared them to molecules identified in a database and produced a "lifestyle profile" of each phone owner.