Without getting into the blatant commercialism on the site, I'll concentrate on the 'detoxification' recommendation of: Coffee Enemas.
These are most often touted as being either detoxifying (as in the Gerson Therapy), a preventative for cancer or a treatment for cancer.
There is no evidence that coffee enemas are beneficial.
Ernst, E. M.D., Ph.d., F.R.C.P. (Edin). Colonic Irrigation and the Theory of Autointoxication: A Triumph of Ignorance over Science. Journal of Clinical Gastroenterology. 24(4):196-198, June 1997. (Make sure to follow the references to the primary sources).
Green, S. A critique of the rationale for cancer treatment with coffee enemas and diet. JAMA. 1992,Dec 9; 269(13),1635-6.
Alison Reed, Nicholas James and Karol Sikora.Mexico: Juices, coffee enemas, and cancer. The Lancet. Volume 336, Issue 8716, 15 September 1990, Pages 677-678.
Cassileth, B. Gerson Regime. Oncology, Volume 24, Issue 2, 2010 Page 201.
There is evidence that coffee enemas can cause harm:
Keum, B. et al. Proctocolitis caused by coffee enemas Am J Gastroenterol. 2010 Jan;105(1):229-30.
I have to go pick up my son from daycare, but I'll discuss the ozone portion shortly.
...shortly is about a week later! Sorry guys! Life intruded.
Nothing on the Gerson page specifically mentions ozone therapy, at least not that I've seen.
Anyone suggesting you inhale ozone is, quite simply, an idiot. They're also putting your health at risk.
Ozone is a pollutant in the atmosphere. (It's vital in the stratosphere, but tropospheric and atmospheric O3 is a pollutant and detrimental to human health.)
Ozone exposure has been long known to exacerbate asthma.
See McConnell, et al Asthma in exercising children exposed to ozone: a cohort study
Ozone in your indoor air will also react with any VVOC, VOC or SVOC - very volatile organic compound (formaldehyde, methanol, methane), volatile organic compound (benzene, limonene), or semi volatile organic compound (PAHs) - the same as it does when it creates photochemical smog outdoors.