Despite what Mrzzy says, the NIH is not backing this fringe therapy. The paper he/she referred to is by Velio Bocci, an Italian who has been pushing this idea for decades, published in a fifth-rate Indian journal, presumably because no reputable one would take it.

A page about ozone from an organization which is really part of the NIH:

http://www.niehs.nih.gov/health/topics/agents/ozone/

This is rather entertaining in a warped sort of way:

http://www.quackometer.net/blog/2009/08/ozone-therapy-homeopath-and-savage.html

Related scams:

http://www.chem1.com/CQ/oxyscams.html