During my relapse, Costco had a sale on for Infrared Sauna which triggered a memory of them being significantly helpful for CFS or IBS. After confirming that on PubMed we purchased one as our Christmas present and used it daily (which may have helped with my remission further). With the Multiple Chemical Sensitivity relapse triggered over Thanksgiving, we have found that it has been very helpful for improving symptoms. In one sense, this should be “common sense” obvious — you sweat out the chemicals that you are sensitive too!
I tend to be very skeptical about “common sense”, especially after hearing all of the common sense cures for Chronic Fatigue Syndrome coming from family, friends and medical professionals. So a review of the current literature on PubMed felt like a good activity to do as a one-year after report to the community. We still use it (although not as frequently as we should — unless there is a flare).
Technically it is called Far Infrared Radiation although the alternative types have been known to use the terms “biogenetic radiation” and “biogenetic rays”; in Japan as “Waon therapy”; in Italy, “phytothermotherapeutic treatment”. This radiation have a lot of low level effect on biological organisms and process. There is evidence that it will help some cancers and encourage other cancers .
Studies have shown for human or animal studies that it helps for following auto-immune (or associated to) conditions:
- Rheumatoid arthritis
- Diabetes Type II 
- Ankylosing spondylitis 
- Allergic rhinitis
- Fibromyalgia ,  “All patients experienced a significant reduction in pain by about half after the first session of Waon therapy “,
- Chronic Fatigue Syndrome  
- Sjögren syndrome 
- Mild depression 
- Chronic Pain 
There were no FIR studies located for Irritable Bowel Syndrome, IBD, UC or Crohn’s — although inference would suggest those would likely also benefit. However we do find some related articles:
- [Possibilities of thermal medicine in gastrointestinal functional disorders]. – with the use of mineral water
- [Clinical-epidemiological study of the efficacy of thermal therapy in gastroenterologic diseases].  – with the use of mineral water
- Thermal hypersensitivity in a subset of irritable bowel syndrome patients[ 2009] found “the subset of IBS patients with high thermal sensitivity (36%) had the highest FBDSI(Functional Bowel Disease Severity Index) score” suggesting a relationship between temperature tolerance and the disease state. Same results from several other studies.
- Evaluation of thermal water in patients with functional dyspepsia and irritable bowel syndromeaccompanying constipation  – “A significant reduction of prevalence of symptoms was observed at the end of the first and second cycles of thermal therapy in dyspeptic and IBS patients”
I was also surprised to find Behavioral treatment of irritable bowel syndrome: a 1-year follow-up study and then found some 33 articles looking at psychological treatment for functional gastrointestinal disorders. The studies are likely valid – in that stress chemicals results in the microbiota changing (and thus we would get statistical results saying that it improves it). Not a single study found that it resulted in remission. This is an important catcha looking at treatments: many treatments may improve most conditions by altering some process that produces a symptom; the treatment may be totally irrelevant to remission of the condition.
What I could not find was any studies on shifts of human microflora (gut bacteria) as a result of the thermal treatment. There was several studies on the successful use of heat (SECCA procedure) for the treatment of fecal incontinence however the latest studies found that the SECCA procedure had 87% of patients with complications and earlier success was not repeated.