The most controversial elements of the program are its heavy use of vitamin B3 (Niacin), which can cause liver damage, and extensive use of saunas beyond what is considered a safe level. Saunas in particular are unsafe for asthma sufferers.
According to the Church's website, the program is a "combination of exercise, vitamins, nutrition and sauna use," which "dislodges drug residues and other toxins from the fatty tissues so that these substances can then be eliminated from the body.
The full procedure is available in the book Clear Body, Clear Mind.
The program is not a weight loss program, and a medical officer's permission is required in advance to start the program. Daily reports monitor the person's condition and progress through the program. The program consists of a course of doses of vitamins (niacin in particular), long periods in a sauna, exercise, and consumption of a blend of vegetable oils. A normal, healthy menu is maintained throughout the procedure. Doses of vitamins are monitored, and are adjusted during the course of the rundown.
The theory is that toxins, drugs, and radioactive particles are stored in body fat, which are released through the exchange of fats (thus the oil consumption) and exercise, and then finally released via perspiration and other normal mechanisms such as body waste. Independent scientific evaluations report that the concentration of toxins or drugs in the sweat is negligible, as they are primarily removed from the body through the liver, the kidneys and the lungs.
Scientific study has shown that niacin assists the body in ridding itself of toxic and harmful chemicals in some situations. In the Purification Rundown Hubbard went further, claiming that large niacin doses (up to 5000 mg) could restimulate and "run out" all manner of past phenomena, including radiation exposure, sunburn, allergies, cancer, gastroenteritis, and anxiety. He noted, "If it is there to be turned on by niacin it will be turned on by niacin." The dosages Hubbard described are within the range known to cause harmful side effects, such as liver damage and stomach ulcers.
The Purification Rundown requires its participants to ingest the following at regular intervals:
Scientologists are strongly encouraged to take part in the Purification Rundown, and this controversial physical purification program is seen as a step towards purifying the spirit as well as the body (as outlined in the book Clear Body, Clear Mind).
The Church of Scientology says that the rundown can improve personality and increase IQ by up to 15-30 points.
The predecessor of the Purification Rundown was known as the 'Sweat Program.' It also featured exercise and sauna use. The prevalence of drug use, pollution, pesticides, and other similar environmental factors has turned the Purification Rundown into a routine part of a pre-clear's auditing program. The process is not publicly claimed by the church as a cure for any specific disease or condition. Scientologists believe that unhandled (untreated) side effects of drugs slow or even stop a person's progress, ability to learn, and spiritual growth.
Today, Scientology promotes the Purification Rundown to the public as a "detoxification" program, while it also works with allegedly non-religious but Scientology-affiliated groups such as Narconon to offer this program as a treatment for addiction and high levels of stress.
Tom Cruise co-founded a fund-raising initiative at Downtown Medical, which collected charitable donations in order to pay for Purification Rundowns for public-sector employees who had been exposed to toxic chemicals during the September 11, 2001 attacks in New York. PR photographs include persons holding up towels soaked through with oddly colored sweat to demonstrate that something good was happening during the program.
Lisa Gengo, a doctor of naturopathy and vice chairman of the department of integrative medicine at the New York College of Podiatric Medicine, is doing an independent review of the program. She says: "I've been there enough to see that people are getting better. I've seen many things that just floor me, people from week to week who look vastly different and are improving in amazing ways." "It's easy to criticize, but people are getting better there and that's what's important. We don't know why aspirin works. We don't know the mechanics of it, but we do know that it works. However, this is incorrect. The mechanism of action of aspirin is known.
In Albuquerque, New Mexico judges are sending substance abuse offenders to a Narconon based rehabilitation center called “Second Chance.” Second Chance is partially federal funded and only treats patients from judicial referrals.
In Salt Lake city the police department is using the Scientology based program to treat police officers that suffer from exposure to meth lab toxins at taxpayer expense.
In New York over 800 9/11 rescue workers have completed the detox program through “New York Rescue Workers Detoxification Project.” The program has been endorsed by some politicians and $630,000.00 of city funds have been diverted towards the program. According to a paper from the International Academy of Detoxification Specialists, the non-profit Scientology project promoting the program, all rescue workers that have completed the detox program reported improved health with 63% reporting to have resolved breathing difficulties. Some of the fire fighters who have gone through the program now speak in favor of it.
The program also involves putting the subjects into saunas, and administering niacin and other vitamins, along with large quantities of various types of vegetable oil, in the belief that the subject will sweat out the toxins and replace the oils in the body's fatty tissues with the vegetable oil. Dr. James J. Kenney, Ph.D., R.D., a member of the National Council Against Health Fraud claims that this technique does the opposite of what it claims . Medical professionals have stated that the ingesting of large amounts of niacin and other vitamins can cause liver and kidney damage. In particular, niacin is both associated with liver damage at high amounts and is prescribed by Hubbard's program at an amount almost three times what the Institute of Medicine's Food and Nutrition Board deems the daily upper limit for an adult.
The notion that radioactive particles can be stored in fat as claimed by Hubbard is considered discredited in modern science. The effects of such high doses of vitamins on the body are also known to pose serious health risks; former members have suffered liver damage from the treatment.
In a 1988 report, Dr. Ronald E. Gots, a toxicology expert from Bethesda, Md., called the regimen "quackery," and noted that "no recognized body of toxicologists, no department of occupational medicine, nor any governmental agencies endorse or recommend such treatment."
Deputy Fire Commissioner Frank Gribbon of the NYFD is on record as being critical of the Rundown used on rescue workers following September 11.
A Scientology disclaimer warns that the procedure is not intended for diagnosis or treatment of physical condition: