A light sensitive substance taken from the herb St John's wort
is being used to treat cancer. Belgian scientists have already
used the substance, hypericin, to detect cancer cells. But they
also believe hypericin could be used to actually kill off
cancerous tumours. Professor Peter de Witte, from Leuven
University in Belgium, has been perfecting a technique known as
Photodynamic Therapy (PDT) for the last nine years. It works by
utilising the light sensitive properties of hypericin to show up
the presence of cancer cells. He said: "We've discovered that
especially bladder tumours that can't be detected through
endoscopy, can be detected with hypericin." The technique is
currently being used to treat 100 patients in Belgium. At
present, surgery is required to remove cancer cells once they
have been located. But Prof de Witte is working on a new
application of PDT to destroy tumours. Source BBC News