Scientists at the University of Pittsburgh have developed a powder which can grow back some missing parts of the body.
Limb regeneration was something previously only thought possible in a few animal species, such as salamanders and geckos.
In humans, only very young children have been seen to re-grow missing finger tips.
Until now, if an adult accidentally chopped off part of a finger, the only hope was to find the severed part and quickly get it sewn back on by surgeons.
However, now a man has watched the end of his finger grow back after applying an extract of powdered pigs' bladders (or "pixie dust" as some call it) to the stump.
The BBC's Matthew Price went to meet the man to investigate.
Listen Listen to Matthew Price's report (4 mins 43 secs)
First broadcast 1 May 2008
Watch the healing process
here
(NB. This video contains images of the severed finger)