What would you do if your swimming pool was dirty?  Clean it of course.  But how?  Would you take out a few pails of water, treat the water in the buckets, then toss the water back into the pool and declare the pool clean?  And if it were the bathroom that needed cleaning, would you clean it by treating a few bucket fulls of water from the pool?  Seems an odd approach to me, but, metaphorically speaking, it is the approach used by ultraviolet (UV) and laser treatment of blood.

A weird bit medical therapy, I get the occasional ‘Hey Dr. Smartypants, what do you think of this treatment?’ email. UV blood irradiation is an odd treatment, with an peculiar history.

UV light does have many effects on tissues, as a trip to Hawaii can rapidly demonstrate to a pasty Oregonian. In my world UV is used to sterilize the environment and UV kills off everything from MRSA to C. difficile to tuberculosis.  We vent potentially microbially contaminated air to the outside in part to dilute any infection but more importantly  we know that most pathogens will die when exposed to solar UV light. Do not use UV light on people as a rule, since it causes tissue damage and we fret about injury to eyes and skin.

Back in the 1930’s a physician named Knott had two patients, one with a brain abscess and one with sepsis, who he evidently cured by irradiating the patients’ blood and returning it to them.*  His rationale was since cutaneous TB can be cured by UV light (the discovery resulted in the 1903 Nobel Prize in medicine and physiology), perhaps other infections would be amenable to the therapy as well (1).250 to 300 cc is the average amount of blood withdrawn, irradiated and returned to the patient.  Given the mythical 70 kg human has about 5 liters of blood, that would mean they were ‘treating’ about 6% blood volume, which is irradiated for 10 seconds. Hardly seems a sufficient volume  and time for treatment of anything.  These studies were done at the beginning of the antibiotic era when sulfa antibiotics were the only commonly used agents.

The mechanism(s) by which UV irradiation are suppose to work include

1)  Bactericidal effects

If they are doing the irradiation for antimicrobial effects it is uncertain how they could  kill off  a significant percentage of the infecting organisms, since the blood stream, if containing germs, usually has much less infection than the source: brain abscess, pneumonia, etc. Irradiating peripheral blood for treating a brain abscess is not unlike the aforementioned cleaning the kitchen by cleaning a bucket of pool water

It was also suggested that the effect on bacteria was indirect. Some in vitro data at the time suggested an increase in phagocytosis  of bacteria by WBC of 50%, but increasing the function of 6% of circulating white cells seems insignificant.  One review recognized it was not reasonable to credit direct bacterial killing:

These favorable clinical results obtained have to been shown to  be due to a tremendous and rapid rise in the patients own resistance to infection rather than to any direct bactericidal effect, though ultraviolet rays are lethal to all common coccal bacteria.  This is not surprising as only 3 percent of the total blood volume is exposed to ultraviolet light during a blood irradiation. Furthermore the amount of ultraviolet irradiation is not sufficient to directly kill bacteria in vitro, although the patient whose septicemic blood was tested recovered with a rapid disappearance of bacteria from the blood stream (3).

2) Detoxification

They note that many bacterial toxins (diphtheria tetanus, botulism; they actually named toxins!) are inactivated by UV light in vitro so it should work in vivo against the toxins made by bacteria.  I can find no papers to confirm this hypothesis.

3) Increased oxygenation

Evidently UV irradiated blood increases oxygen content, although I cannot find a modern confirmation of a beneficial effect.

4) Vaccine Effect

A  somewhat incoherent suggestion that since UV irradiation can lead to immunizing agents (irradiated viruses are not infectious but can elicit immunity), perhaps the same is occurring with UV irradiation of blood.  Herpes and Staphylococcal furuncules are given as examples where UV irradiation of blood led to resolution of diseases by a vaccine effect.  Since none of the causative agents are in the blood at the time of the irradiation, it is difficult to imagine how enhancing ‘vaccine’  effect could occur.

One site explains it thus:

the UV light concurrently kills infecting organisms, making them “antigenic.” This means the fragments of the killed infecting agents create a safe, autogenous vaccination-like response. This further activates and directs your immune system to the specific infections your body is attempting to overcome. The net result is the induction of a secondary kill of these infecting agents throughout the entire body. Thus, treating only 35 cc of your blood with UBI induces a beneficial systemic response.

If they were doing the irradiation for immunomodulation, as best I can tell (and most of the modern literature is for the treatment of psoriasis  ) UV is immunosuppressing, which may help modulate the clinical course of sepsis (which is due to an overactive response to infection) but should make all other infections worse.

5) Photosensitization

UV interacts with never elucidated molecules and activates those molecules to kill bacteria, much as acridine exposed to UV light will kill paramecia.

6)  Other effects  with UV  treatment of blood that were thought important and real included vasodilatation, desensitization (sort of the opposite of the vaccine effect)  and a reduction in edema.  One site suggests that some of the UV light is stored in the blood  and then released after it is infused  to kill bacteria in a burst of intravascular radiation.

There was fairly widespread use after the initial reprots. One review in 1949 suggested 60,000 people had received the therapy over the prior 15 years (2).  There were no randomized placebo controlled trials that I could find, but  a number of  impressive case series of very ill patients: sepsis, abortion, peritonitis, gall bladder disease,  and the acute surgical abdomen. Patient after patient ill with serious bacterial infections improving when medicine was little better than using stone-knives and bear-skins.   It appeared to be highly effective with minimal toxicity for the treatment of many infections and some other diseases as well such as cancer (of course) and asthma. And no side effects worth reporting.

There were many obvious problems with the papers: no randomized, placebo controlled trials, just collected anecdotes, and as we all know the plural of anecdote is anecdotes not data,  But they are an impressive series of anecdotes nonetheless.  The studies make you wonder whether a legitimate effect is really occurring. Of course the same could be said for internal mammary artery ligation of angina. 

It is  a worry that most of the literature was generated by three researchers.  Many of the case reports were a wee bit too dramatic, almost at the level of miracles than medicine

Botulism, a uniformly fatal condition, was treated by Miley. The patient was in a coma and could not swallow or see. Within 48 to 72 hours of one irradiation treatment, the patient was able to swallow, see, and was mentally clear.  She was  discharged in excellent condition in a total of 13 days.


Results of recovery were 100% for early infections, 46 out of 47 for moderately advanced, and 17 out of 36  of those who were  moribund. Staphylococcus had a high death rate, but those patients were also using sulfa drugs, which may have inhibited  the  effectiveness of the UV irradiation treatments. In fact, when Miley reviewed  his  data,  he found that all the Staph failures had been on sulfa. A second series of nine patients (six Staph aureus, three Staph albus) had  a  100% recovery rate with one or two treatments when sulfa was not used.

When a treatment seems too good to be true it probably is.  The stories are so uniformly positive with no side effects it doesn’t seem legitimate, but I have no way to know without access to the original data. He waxes desperate with imagination…Something is rotten in the state of Denmark. But the papers don’t ‘smell’ right.

Then the therapy just vanishes in the medical literature and I can’t determine why.  There wasn’t a seminal study that demonstrated UV blood irradiation was not effective.  Evidently it was a fad that just vanished like hula hoops, mullet haircuts and Uggs (well, I can wish). Even sites like the Whale, which I would have expected to have some anti medical-industrial complex conspiracy theory, fails to have an explanation, just that modern medicine came to prefer medications over UV light. Anyone practicing at the time have any insight?

Just because the technique disappeared from standard medicine doesn’t mean it is not still used.  Multiple machines are available for purchase  and appear to run around $5,000,  and, as would be expected, the indications for UV light therapy have broadened:

Ultraviolet Blood Irradiation has been used to treat the following conditions:
•    Allergies – inhaled and food.
•    Autoimmune diseases such as lupus, rheumatoid arthritis and Sjorgen’s Syndrome.
•    Cancer – various types including breast, colon and prostate.
•    Chronic candidiasis  – chronic yeast overgrowth.
•    Chronic fatigue syndrome and conditions.
•    Mononucleosis
•    MRSA infections
•    Multiple sclerosis
•    Osteomyelitis
•    Pain
•    Peripheral vascular disease.
•    Shingles

•    Toxicity

And more.  It depends on what web site you visit.  One treatment for everything.

Of course, UV is so last century.  Now they use lasers to irradiate the blood.  Both as a modification of the Knott technique where a laser is used in place of UV light  or by sticking a laser in your nose to irradiate the blood passing through the nasal mucosa. Really.  This is not fiction.  Check out the Wikipedia page and giggle.

There are a smattering of Pubmed papers mostly out of Russia  using “laser “blood irradiation”” as search terms, where the bulk of the laser blood irradiation research is done, and the abstracts gave me insufficient understanding  as to what they are doing.
As an example

The authors report a bacteriostatic effect of He-Ne laser irradiation on Tb growth. Endovascular blood irradiation used in 85 tuberculous patients induced no side effects. Ten-twelve sessions relieved the symptoms of tuberculosis-related intoxication, reduced the infiltration and destruction, promoted abacillosis. Laser irradiation holds promise in management of torpid infection and hepatotoxicity induced by isoniazid and rifampicin. The highest effect occurred in infiltrative tuberculosis.

Laser blood irradiation is also used for preop in surgery to decrease infections,  treat cardiac arrhythmia’s and glomerulonephritis, all with salubrious effects.  Color me skeptical that irradiating a small volume of blood could have beneficial effects on such a wide range of diseases with such disparate pathophysiologies.

To date, I still think the only wonder drug that works wonders is Bayer aspirin.  UV and laser treatment of blood, for all the impressive case reports from 50 years ago, is neither tried nor true by the standards of modern medicine and science.  I suspect it died as it was not effective and probably can’t have any effect. From basic principles it appears to be almost the homeopathic application of light.  The effects are from N-rays  more than UV or Laser rays.


* There are, to my discomfiture, many second hand sources for my information.  Many of the references are not available though the interwebs or Pubmed and I do not ask my library for copies of papers when they get charged and it is not for direct patient care.


  1. Miley, George, Ultraviolet Blood Irradiation Therapy (Knott Technique) in Non-Healing Wounds, American Journal of Surgery, Vol. 65, No. 3, September, 1944, pp. 368-372.
  2. The role of ultraviolet blood irradiation therapy; Knott technic in surgery. OLNEY RC. J Int Coll Surg. 1949 May-Jun;12(3):353-6)
  3. Miley and Christensen, Ultraviolet Blood Irradiation Therapy in Acute Virus and Virus-Like Infections, The Review of Gastroenterology, Vol. 25, No. 4, April, 1948, pp. 271-276.Miley and Christensen, Ultraviolet Blood Irradiation Therapy in Acute Virus and Virus-Like Infections, The Review of Gastroenterology, Vol. 25, No. 4, April, 1948, pp. 271-276.


Posted by Mark Crislip

Mark Crislip, MD has been a practicing Infectious Disease specialist in Portland, Oregon, since 1990. He is a founder and  the President of the Society for Science-Based Medicine where he blogs under the name sbmsdictator. He has been voted a US News and World Report best US doctor, best ID doctor in Portland Magazine multiple times, has multiple teaching awards and, most importantly,  the ‘Attending Most Likely To Tell It Like It Is’ by the medical residents at his hospital. His growing multi-media empire can be found at edgydoc.com.