I can only find one human study using the term "soil organisms" published in a reliable peer reviewed medical journal. This page will be updated if such research becomes available in the future. The term " homeostatic soil organisms " is used, but I have no idea what people mean by the word " homeostatic " as it relates to soil organisms. This term may just be a marketing ploy.

A review of Medline in March 2016 did not reveal any new studies.

What are homeostatic soil organisms?
There is no explanation made as to the composition. What are these? What soil do they come from? How are they processed? Are homeostatic soil organisms from one region different than another region, state, country, etc? How do we know there are no harmful bacteria, fungi, or other organisms that could cause long term infection? How do we know these products are any better than regular probiotics or any other natural treatment with more research backing findings? How are homeostatic soil organisms sold by one company different than the ones sold by another?

Definition in an Encyclopedia
Soil organisms are any organism inhabiting the soil during part or all of its life. They range in size from microscopic cells that digest decaying organic material to small mammals. They also break down plant and animal tissues, releasing stored nutrients and converting them into forms usable by plants. Some soil organisms are pests. Among these that are pests of crops are nematodes, slugs and snails, symphylids, beetle larvae, fly larvae, caterpillars, and root aphids. Some cause rots, some release substances that inhibit plant growth, and others are hosts for organisms that cause animal diseases.
   As you can see, this term is quite vague and one has no idea when ingesting such a product what actually is present in it.

Soil bacteria can influence immune system
Exposure to a soil bacteria could improve mood by influencing the immune system. Researchers exposed mice to a harmless soil microbe called Mycobacterium vaccae and had the rodents perform a behavioral task commonly used to test the efficacy of antidepressant drugs. The mice were placed in a large beaker of water for five minutes and watched to see how long they continued swimming and searching for an exit before giving up. The researchers found that the Mycobacterium vaccae bacteria-exposed mice continued paddling around much longer than the control mice. Results from the new study are similar to those from a medical trial a few years ago in which human cancer patients treated with Mycobacterium vaccae bacteria reported increases in mood and their quality of life. However, Mycobacterium vaccae use in these cancer patients was not studied any further because it didn’t prolong life. Mycobacterium vaccae bacteria may affect the brain indirectly by causing immune cells to release chemicals called cytokines which influence neurotransmitters such as serotonin. Could the use of small amounts of 5-HTP offer the same benefit?.

Emails from readers
Q. I'm not a scientist but I do speak English as well as the next guy and I'd like to give you my opinion of what "homeostatic" means in the phrase "homeostatic soil organisms" (HSO). I think that Garden of Life is trying to say, in its marketing-slanted, buzz wordy, kind of way, that the organisms in question maintain their same basic metabolism and morphology when transplanted from soil to gut. Does that make sense to you?
   A. Maybe, we're puzzled by the use of this term.

Q. I have just finished reading your q&a page on HSOs and I am extremely irritated. Your biggest argument with Jordin Ruben (sic) is that his findings haven’t been published in any medical journals. LMAO. Because we’re supposed to trust big pharm to have our best interests at heart, right? I was standing in the health food store back in the 90’s when the FDA came in with guns removing co-q10. Big pharm wasn’t too happy when all of these people with congestive heart failure start taking it and become well and are living full ,incredible lives. Why does Big Pharm not recognize HSOs? BECAUSE IF PEOPLE FIGURED OUT THAT ALL THEY HAD TO DO WAS EAT EXACTLY HOW GOD INTENDED FOR US TO EAT (directly from the earth), THERE WOULD BE NO REASON FOR YOUR PROFESSION!
   A. The fact that claims are being made by certain supplement companies promoting the benefits of "homeostatic" soil organisms without evidence that they are effective has nothing to do with big pharma. There are plenty of natural supplements that have had good research to show benefits, and I mention and recommend those in many articles on my website. If there were research that showed HSO supplements provided benefits, I would mention them. If anyone knows of such research, let me know.
   People can eat an excellent diet, eating all organic and direct from earth, yet still become ill and have health issues. The medical profession, even with all its flaws, is an admirable profession. I doubt if anyone would like to go back to the days before antiobiotics, pain medications, and effective anesthesia were discovered.

Q. Recently, I purchased a product containing bacterial soil organisms. I found an article today by Jini Patel Thompson, author of the book, the "IBD Remission Diet." In the article she quotes Natasha Trenev who she says is a "world renowned expert on microorganisms and maintains one of the largest research libraries on that topic in the world." She says, "Tenev outlines why it is not safe to consume bacterial soil organisms ." She states, "To summarize the research briefly, soil organisms (SO) are spore formers, so they make make good competitors for yeast, fungus and other pathogens. This is why so many people taking soil organisms will initially experience very favorable results. However these spores are are extremely difficult to kill, surviving sterilants, disinfectants, acceleration forces, heat, pressure, radiation and many antibiotics. Strong antibiotics -- like Vancomycin -- can suppress certain spores. Spores are so persistent in the intestines that another round of germination may occur after the the drug is stopped. Soil organisms can also adapt loose genetic material and incorporate it into their cellular structure - the ramifications of which are yet unknown. Various soil organisms can also produce harmful peptides, affecting hemoglobin in the blood. It's important to keep in mind that virtually all antibiotic drugs were were initially developed from soil organisms and as antibiotics become more potent, they cause more damage to the host, not just in the immediate gut environment, but systematically as well. There are simply too many questions and unknowns to sanction the use of soil organisms for human consumption and one can certainly cannot qualify them as safe at this time." Is this true? I'm very concerned about my health, and, after reading this article, I'm hesitant to take the products I've ordered. There is so much misinformation in the alternative health field that it is hard to know what to believe. I appreciate any assistance you can give in this matter.
   A. I have come across only one reliable human study regarding a particular soil organism called Mycobacterium vaccae, and hence it appears that any claims made for or against the use of soil organisms are premature and not based on any solid clinical evidence.

Q. I read on a website about homeostatic soil organisms. This is what is says: HSOs optimize the digestive terrain and immune function as they move through the digestive tract and form colonies along the intestinal walls. What is your opinion?
   A. I have no idea what it means to call these supplements  "homeostatic "soil organisms. I have only seen one good human study regarding soil organisms let alone " homeostatic soil organisms." It appears to me, at first glance, that marketing of soil organism supplement is far, far ahead of any clinical studies.

Q. There is plenty of positive anecdotal comments on homeostatic soil organism according to Jordan Rubin, founder of Garden of Life products. I realize anecdotes do not carry the same weight as carefully controlled research, but it should not be dismissed out of hand. Depending on the sources, this type of information can be very informative.
   A. Yes, anecdotes can be helpful, depending on the source and the integrity of the source. It's helpful if the source of the anecdotes is not the person or the company selling the products. If you come across additional published studies on homeostatic soil organisms, please let us know.

Q. Are homeostatic soil organisms supplement preferable to acidophilus or probiotics for gastrointestinal disorders?
   A. Since I have not seen any independent published studies with homeopathic soil organisms, and none comparing homeopathic soil organisms to a probiotic supplement, it is impossible to say.

Q. I came across marketing information about a product called Primal Defense. The person at the health food store who was trying to sell it to me claimed that HSO homeostatic soil organisms make this a unique product better than prebiotics or probiotics on the market. What are your thoughts about Primal Defense? They also say something about Poten-Zyme and ionic plant based minerals. It was confusing. I wanted your opinion since I trust what you say.
    A. I prefer not to comment products from other companies, but I can comment about ingredients in products. It appears that this product has probiotics and HSO homeostatic soil organisms. I have no idea what they mean by homeostatic, it appears to be a marketing sales term, I also have no idea what they mean about Poten-Zyme, and Ionic plant based minerals. What do they mean about 'Ionic' plant based minerals? The word ionic used in this context makes no sense to me as a medical doctor with a bachelor's of science degree in Nutrition. Perhaps someone reading this web page can explain to me what Poten-Zyme or ionic plant based minerals are. As to other ingredients in Primal Defense, it appears to have good probiotics such as lactobacilli and bifidobacterium. But then again, there are countless good probiotic products available but many different companies.

I read you article on Primal defense and found it quite informative. I have had Crohn's disease for about 30 years and have been on all the standard drugs. About 5 years ago I decided to try and take charge of my disease and learn all I could to see if I could get off the terrible drugs (Predinsone being the worst). I started researching probiotics and whip worm parisites and learned some very hepful and questionable information. I decided to try the Primal Defence probiotics. I was currently at the time on 4 Asacol a day which helped lessen the symptoms only. I followed the instrutions (I had to stop taking all other meds) and within 4 days ALL my symptoms were gone. I never knew people felt this good. I have been disease free know for 5 years. I had my last colonoscopy 2 years ago and all sign of the disease was gone. My specialst was amazed. I told him what I had done and he told me he had read reports with some people having these results. I guess I got lucky. I find your site very infomative and will continue to read it. I sent you this in the hopes that you may be able to use some of this info for future research. If I can help even one person with this terrible disease I would be happy to do it.

Q. I noticed on your web-site that you were asking for research on Homeostatic Soil Organisms. I found an article on the web that claims to have done research on Homeostatic Soil Organisms from Jordan S. Rubin version of this medication. This is the link to the article. The article was published in the Townsend Letter for Doctors and Patients written by Dr. Paul Goldberg in Nov. 2002. http://www.findarticles.com/p/articles/mi_m0ISW/is_2002_Nov/ai_93736412
   A. Thanks. We reviewed the article. We're surprised it has not been submitted to peer review process in a medical journal. A brief review of this article raises a number of suspicions about the objectivity of the researcher and the accuracy of the findings themselves. Here are some of the ones I mean:
    Dr. Goldberg, a chiropractor, says, "I respect that the president of the company that produces Primal Defense, Dr. Jordan Rubin, had himself experienced serious illness, and that the product was developed because of his own problems with chronic disease."
          Response: Jordan Rubin is not a doctor, and if Dr. Goldberg believes that Jordan Rubin cured his "illness" with Primal Defense, then he is more gullible than it initially appears. What proof is there that Jordan Rubin cured his illness with homeostatic soil organisms? His word alone? Does Dr. Goldberg believe everything a marketer tells him?
   Dr. Goldberg continues, "The study results were significant. There were impressive clinical improvements in most clients without any side effects, as noted in the study that follows. Despite these findings, I do not believe the product to be of significant value unless the patient is also willing to make the needed dietary / hygienic / lifestyle reforms."
        Response: This makes no sense. Either a product works by itself, or it doesn't. If the product does not have significant value, how can Dr. Goldberg say that the study results were significant. This is shoddy research, at best.
   Dr. Goldberg continues: "It has been suggested, that bacteria found in the soil referred to as Homeostatic Soil Organisms (HSOs), when ingested orally in a probiotic formulation, may have advantages over non-HSO probiotic formulas, due to their ability to implant and survive in the gut. The value of HSOs reportedly lies in promoting positive intestinal function, with corresponding systemic improvements in the patient's overall nutritional, immunological and gastrointestinal status."
        Response: "it has been suggested...." is not a good enough statement when writing a research paper. What proof does Dr. Paul Goldberg have regarding the statements he makes?
   Dr. Goldberg says: "Subjects were told to take adequate care of your general health, by avoiding processed foods, getting sufficient rest and sleep, and not engaging in toxic habits, specifically alcohol, tobacco, or any drugs other than needed prescription medications."
        Response: This alone can make a difference in health. There was no placebo controlled arm of the study.
        Summary: Rather than good science, Dr. Paul Goldberg appears to me to be just a marketing extension for Primal Defense. His bias is apparent and in my opinion this "research" cannot be relied on. There is no explanation made as to the composition of the homeostatic soil organisms. What are these homeostatic soil organisms? What soil do they come from? How are they processed? Are homeostatic soil organisms from one soil region different than another region, state, country, etc? How do we know there are no harmful bacteria that could cause long term infection? How do we know homeostatic soil organisms are any better than regular probiotics that are a fraction of the cost of Primal Defense?

Q. Google sent me first to your page on " homeostatic soil organisms. "  Thank you for your restraint in reviewing much-hyped topics.

Q.  I am emailing you in regard to the soil organisms information on your web site. Have you seen this article on Homeostatic Soil Organisms - Clinical Studies a at http://www.crohns-disease-probiotics.com/HSOs.html I find that they have some interesting studies. Three single-blind, placebo-controlled studies on HSOs seems pretty good evidence.
   A. We did a search on Medline for " Primal Defense :and could not find any published studies. We also did a search for " Homeostatic Soil Organisms " and again no studies were found. If such studies regarding Homeostatic Soil Organisms have been done, we are puzzled that they have not been submitted to peer reviewed and independent medical or scientific journals. 

Q. I have Crohns disease, I have to take the way too-expensive Pentasa, and the more reasonable Imuran, I also take aloe vera and probiotic Acidophilus. Plus I eat yogurts. I eventually got really sick and dropped 45 pounds in 2 months, had 15 inches of my intestine removed, because medications like Prednisone and all the other meds listed above, didn't not help. Right now...my blood work is *Ok* but slightly elevated. BUT... I am still getting extreme spasms. I don't want another *Flare-up* and I do not have medical insurance or prescription coverage. If HSO homeostatic soil organisms has yet to be proven, and proven to be helpful, what else is available for me to try? Am I doomed to more surgeries, and possible death? Should I try the homeostatic soil organism supplements?
   A. You are going through very difficult times. However, it is up to you and your doctor to decide on the proper courses of action. Perhaps you can review some of the information on this website regarding natural options for Crohn's disease.

Q. I was recently reading your Q&A age about Homeostatic Soil Organisms. You mention that you have seen only the one research article on soil organisms. I agree with you that the Homeostatic word is probably just a marketing ploy, but when they mention soil organisms I believe that is just referring to the addition of bacillus subtilis to the probiotic. And there certainly have been journal articles written about that bacteria. Here is one for example. Bacillus subtilis: A Shocking Message from a Probiotic. Cell Host & Microbe, Volume 1, Issue 4, Pages 248 - 249. P . Williams.
   A. If you are familiar with human studies regarding the ingestion of soil organisms, please let us know. Also, if you know which organisms are accepted as appropriate for human consumption, and what the ideal dosages would be, and whether there are side effects or concerns regarding the ingestion of these soil organisms, we would appreciate any links you provide.

Vitamineral Green offers a supplement that includes soil-based organisms. Prescript-Assist offers a probiotic supplement of only soil-based organisms. Other products also contain them. Are soil-based organisms safe? Are they superior or equal to acidophilus, etc, probiotics?
    I have seen no evidence that they are safe or not safe, nor any comparison studies regarding any advantages or disadvantages compared to probiotics. Probiotics have been studied quite extensively and I prefer using them for the time being.

I was reading a page on your website relative to "HSO's" and decided to do a little surfing to find out what else I could find that was user friendly, in that it used layman's terminology. This article is from 2004 but as far as I know it is still very relevant. There are not enough studies done on this topic. I found it very interesting since it looks at SBO's (Soil Based Organisms, aka HSO's ) essentialformulas dot com September 2004.

In your discussion it appears that you have not found information as to the specific origin of the term "HSO" or Homeostatic soil organisms. Just moments before finding your page I was reading a well known book in which the author describes how he came to originate that term. So far I haven't found an "explanation" but its fairly certain this individual came up with that term, though he did not apparently invent of find the organisms to begin with. Somehow the name has stuck, perhaps because of his books which use the term. The author's name is Jordan S. Rubin, N.M.D., C.N.C. and the book in which this term is introduced is "Patient Heal Thyself". I personally have never encountered this particular product and this is the first I've heard of it so don't have any details to share other than to point you to the source of the term in question. Perhaps that would make your web page more informative as opposed to guessing where it came from.

I noticed a page in which Dr Sahelian stated he found only one paper on this topic. I haven’t the time to look into this, but Dr Carolyn Dean (MD, ND) stated: “More than a decade of clinical studies on Prescript Assist have shown no adverse effects or side-effects on all types of populations even at dosages 500 times the recommended amounts. I wish I knew about this product when I was writing IBS for Dummies (with my sister) because Prescript Assist is a scientifically-researched, effective treatment for IBS and leaky gut. Anecdotal cases are accumulating about its benefits for intestinal yeast and fungal skin infections.”
   A. I am not aware of such studies as Dr. Carolyn Dean MD claims.