Gut & colon health

Sources

Every numbered claim on the overview and article pages is listed here with the exact passage it rests on. 72 passages were checked word-for-word against the saved copies listed below.

Pharmacist review pending72 verified passagesUpdated 2026-10-22

Current evidence

1

Bacteria in your digestive tract — your gut flora or microbiome — help with digestion.

“Bacteria in your GI tract, also called gut flora or microbiome, help with digestion.”

NIDDK (U.S. National Institutes of Health) — Your Digestive System & How It WorksPassage verified word-for-word in saved copy
2

Bacteria in the large intestine help break down remaining nutrients and make vitamin K.

“Bacteria in your large intestine help break down remaining nutrients and make vitamin K.”

NIDDK (U.S. National Institutes of Health) — Your Digestive System & How It WorksPassage verified word-for-word in saved copy
3

Bacteria in the small intestine make some of the enzymes you need to digest carbohydrates.

“Bacteria in your small intestine make some of the enzymes you need to digest carbohydrates.”

NIDDK (U.S. National Institutes of Health) — Your Digestive System & How It WorksPassage verified word-for-word in saved copy
4

Nerves, hormones, bacteria, blood and the digestive organs work together to digest what you eat and drink.

“Working together, nerves, hormones, bacteria, blood, and the organs of your digestive system digest the foods and liquids you eat or drink each day.”

NIDDK (U.S. National Institutes of Health) — Your Digestive System & How It WorksPassage verified word-for-word in saved copy
5

The microbiome is all the microbes — bacteria, fungi, viruses and their genes — that naturally live on and inside us.

“The microbiome is the collection of all microbes, such as bacteria, fungi, viruses, and their genes, that naturally live on our bodies and inside us.”

NIEHS (U.S. National Institutes of Health) — MicrobiomePassage verified word-for-word in saved copy
6

These microbes protect us against germs that cause disease, help the immune system develop, and help us digest food for energy.

“They protect us against pathogens, help our immune system develop, and enable us to digest food to produce energy.”

NIEHS (U.S. National Institutes of Health) — MicrobiomePassage verified word-for-word in saved copy
7

There are as many microbes as human cells in the body, and each site — gut, skin, mouth, nose — has its own community.

“there are as many microbes as there are human cells in the body”
“each body site – for example, the gut, skin, and oral and nasal cavities – has a different community of microbes.”

NIEHS (U.S. National Institutes of Health) — MicrobiomePassage verified word-for-word in saved copy
8

Your core microbiome forms in the first years of life, but it can change over time with diet, medications and environmental exposures.

“A person’s core microbiome is formed in the first years of life but can change over time in response to different factors including diet, medications, and environmental exposures.”

NIEHS (U.S. National Institutes of Health) — MicrobiomePassage verified word-for-word in saved copy
9

Disrupting the microbiome could increase the likelihood of conditions such as diabetes, obesity, heart and nerve diseases, allergies and inflammatory bowel disease — an area still being researched.

“Environmental exposures can also disrupt a person’s microbiome in ways that could increase the likelihood of developing conditions such as diabetes, obesity, cardiovascular and neurological diseases, allergies, and inflammatory bowel disease.”

NIEHS (U.S. National Institutes of Health) — MicrobiomePassage verified word-for-word in saved copy
10

Many of the links come from animal research — for example, stress and a high-fat diet changing the gut microbes of mice.

“Chronic stress disturbs the gut microbiome in mice”
“a high-fat diet affected the gut microbiome of mice”

NIEHS (U.S. National Institutes of Health) — MicrobiomePassage verified word-for-word in saved copy
11

Big questions remain, including whether today’s tools for changing the microbiome are good enough to prevent disease.

“Yet big questions remain and are the focus of continuing research supported by NIEHS.”
“Are current tools for manipulating the microbiome sufficient to develop interventions to prevent disease?”

NIEHS (U.S. National Institutes of Health) — MicrobiomePassage verified word-for-word in saved copy
12

Researchers are still exploring the links between changes in the microbiome and various diseases.

“researchers around the world, including many supported by NIH, are now exploring the links between changes in the microbiome and various diseases.”

NCCIH (U.S. National Institutes of Health) — Probiotics: Usefulness and SafetyPassage verified word-for-word in saved copy
13

The gut holds a complex, diverse community of bacteria, and many of them help the body work properly.

“The body, especially the lower gastrointestinal tract (the gut), contains a complex and diverse community of bacteria. Although we tend to think of bacteria as harmful “germs,” many bacteria actually help the body function properly.”

NCCIH (U.S. National Institutes of Health) — 6 Things To Know About ProbioticsPassage verified word-for-word in saved copy
14

Some bacteria help digest food, destroy disease-causing cells or produce vitamins.

“Some bacteria help digest food, destroy disease-causing cells, or produce vitamins.”

NCCIH (U.S. National Institutes of Health) — Probiotics: Usefulness and SafetyPassage verified word-for-word in saved copy
15

Probiotics are live microorganisms, the same as or similar to ones found naturally in the body, that may be beneficial to health.

“Probiotics are live microorganisms (e.g., bacteria) that are either the same as or similar to microorganisms found naturally in the human body and may be beneficial to health.”

NCCIH (U.S. National Institutes of Health) — 6 Things To Know About ProbioticsPassage verified word-for-word in saved copy
16

Different probiotics have different effects: if one kind helps, another kind — even a close relative — may not.

“Different types of probiotics may have different effects. For example, if a specific kind of Lactobacillus helps prevent an illness, that doesn’t necessarily mean that another kind of Lactobacillus or any of the Bifidobacterium probiotics would do the same thing.”

NCCIH (U.S. National Institutes of Health) — Probiotics: Usefulness and SafetyPassage verified word-for-word in saved copy
17

In most cases we still don’t know which probiotics help, how much to take, or who is most likely to benefit.

“However, in most instances, we still don’t know which probiotics are helpful and which are not. We also don’t know how much of the probiotic people would have to take or who would be most likely to benefit.”

NCCIH (U.S. National Institutes of Health) — Probiotics: Usefulness and SafetyPassage verified word-for-word in saved copy
18

There is some evidence for acute diarrhea, antibiotic-associated diarrhea and eczema; for most other conditions, strong evidence is lacking.

“There is some evidence that probiotics may be helpful for acute diarrhea, antibiotic-associated diarrhea, and atopic eczema”
“strong scientific evidence to support other uses of probiotics for most conditions is lacking.”

NCCIH (U.S. National Institutes of Health) — 6 Things To Know About ProbioticsPassage verified word-for-word in saved copy
19

The FDA has not approved any health claims for probiotics.

“the U.S. Food and Drug Administration (FDA) has not approved any health claims for probiotics.”

NCCIH (U.S. National Institutes of Health) — 6 Things To Know About ProbioticsPassage verified word-for-word in saved copy
20

Many probiotics are sold as dietary supplements, which don’t need FDA approval before they go on sale.

“Many probiotics are sold as dietary supplements, which don’t require FDA approval before they are marketed.”

NCCIH (U.S. National Institutes of Health) — Probiotics: Usefulness and SafetyPassage verified word-for-word in saved copy
21

The risk of harm is greater with severe illness or a weakened immune system, and severe or fatal infections have been reported in premature infants.

“The risk of harmful effects from probiotics is greater in people with severe illnesses or compromised immune systems.”
“Cases of severe or fatal infections have been reported in premature infants who were given probiotics”

NCCIH (U.S. National Institutes of Health) — Probiotics: Usefulness and SafetyPassage verified word-for-word in saved copy
22

Probiotics have a long history of apparently safe use in healthy people, but few studies have looked at safety in detail.

“Probiotics have an extensive history of apparently safe use, particularly in healthy people. However, few studies have looked at the safety of probiotics in detail”

NCCIH (U.S. National Institutes of Health) — Probiotics: Usefulness and SafetyPassage verified word-for-word in saved copy
23

Probiotics are named by genus, species and strain — for example Lacticaseibacillus rhamnosus GG.

“Probiotic microorganisms are named by their genus, species, and strain.”
“An example of a common probiotic microorganism is Lacticaseibacillus rhamnosus GG.”

NIH Office of Dietary Supplements — Probiotics - Fact Sheet for ConsumersPassage verified word-for-word in saved copy
24

A higher CFU count on the label does not by itself mean more benefit.

“Higher CFU counts alone do not necessarily mean that the product has greater health benefits.”

NIH Office of Dietary Supplements — Probiotics - Fact Sheet for ConsumersPassage verified word-for-word in saved copy
25

Microorganisms make fermented foods such as yogurt, cheese, pickles, kimchi and sauerkraut — but not all of them contain probiotics with proven benefits.

“Microorganisms are used to produce fermented foods, including yogurt, cheese, sourdough bread, pickles, apple cider vinegar, kombucha, miso, kimchi, and sauerkraut.”
“while microorganisms are used to make these foods, not all these foods necessarily contain probiotics with proven health benefits.”

NIH Office of Dietary Supplements — Probiotics - Fact Sheet for ConsumersPassage verified word-for-word in saved copy
26

There are no official recommendations for probiotics in healthy people. If you want to try one, ask your provider which one, what dose and for how long.

“There are no official recommendations that cover the use of probiotics by healthy people. If you want to try probiotics, ask your health care provider for advice about which probiotic to choose, what dose to take, and how long to use the product.”

NIH Office of Dietary Supplements — Probiotics - Fact Sheet for ConsumersPassage verified word-for-word in saved copy
27

Antibiotics can kill helpful microorganisms in the digestive tract, which sometimes causes diarrhea.

“Antibiotics, such as erythromycin and penicillin, can kill beneficial microorganisms that live in the digestive tract, which sometimes results in diarrhea.”

NIH Office of Dietary Supplements — Probiotics - Fact Sheet for ConsumersPassage verified word-for-word in saved copy
28

In a review of studies in people who were not in hospital, probiotics given with antibiotics were linked to about half the likelihood of antibiotic-associated diarrhea — a tentative finding from moderate-quality studies.

“giving probiotics to patients along with antibiotics was associated with a decrease of about half in the likelihood of antibiotic-associated diarrhea. However, this conclusion was considered tentative because the quality of the studies was only moderate.”

NCCIH (U.S. National Institutes of Health) — Probiotics: Usefulness and SafetyPassage verified word-for-word in saved copy
29

Antibiotics don’t work on viral infections, and taking them when they aren’t needed won’t help — but can cause side effects.

“Taking antibiotics when they're not needed won't help you, and they can have side effects.”
“Antibiotics do not work on viral infections.”

MedlinePlus (U.S. National Library of Medicine) — AntibioticsPassage verified word-for-word in saved copy
30

One antibiotic side effect is C. diff infection, which causes diarrhea that can severely damage the colon. Call your provider about side effects while taking an antibiotic.

“C. diff infections, which cause diarrhea that can lead to severe colon damage and sometimes even death”
“Call your health care provider if you develop any side effects while taking your antibiotic.”

MedlinePlus (U.S. National Library of Medicine) — AntibioticsPassage verified word-for-word in saved copy
31

Follow the directions carefully, and don’t share your antibiotic with others.

“Always follow the directions carefully.”
“Don't share your antibiotic with others.”

MedlinePlus (U.S. National Library of Medicine) — AntibioticsPassage verified word-for-word in saved copy
32

Gas and bloating from more fiber often settle once your gut bacteria get used to it; add fiber gradually over a few weeks.

“This problem often goes away once the natural bacteria in the digestive system get used to the increase in fiber.”
“Add fiber gradually over a period of a few weeks to avoid stomach distress.”

MedlinePlus (U.S. National Library of Medicine) — FiberPassage verified word-for-word in saved copy
33

Most high-fiber foods contain both types of fiber, so eat a variety of vegetables, fruits, whole grains, legumes and beans.

“Most high-fiber foods contain both types of fiber.”
“That's why you should eat a variety of vegetables, fruits, whole grains, and legumes and beans.”

MedlinePlus (U.S. National Library of Medicine) — FiberPassage verified word-for-word in saved copy
34

Americans eat about 16 grams of fiber a day on average; the recommendation for older children, teenagers and adults is 21 to 38 grams.

“On average, Americans now eat about 16 grams of fiber per day. The recommendation for older children, adolescents, and adults is to eat 21 to 38 grams of fiber each day.”

MedlinePlus (U.S. National Library of Medicine) — FiberPassage verified word-for-word in saved copy
35

A 2015 review found no compelling research supporting “detox” diets for weight or for removing toxins from the body.

“A 2015 review concluded that there was no compelling research to support the use of “detox” diets for weight management or eliminating toxins from the body.”

NCCIH (U.S. National Institutes of Health) — “Detoxes” and “Cleanses”: What You Need To KnowPassage verified word-for-word in saved copy
36

Evidence for colonic irrigation is limited, colon cleansing can have serious side effects, and some cleanse programs are unsafe or falsely advertised.

“There is limited clinical evidence validating colonic irrigation and insufficient evidence for its prescribed uses. Colon cleansing procedures may have side effects, some of which can be serious.”
“Some “detoxification” or “cleansing” programs can be unsafe and falsely advertised.”

NCCIH (U.S. National Institutes of Health) — “Detoxes” and “Cleanses”: What You Need To KnowPassage verified word-for-word in saved copy
37

Talk with your provider before a probiotic supplement, and don’t replace proven treatments with unproven products.

“If you are considering a probiotic dietary supplement, talk with your health care provider first. Do not replace scientifically proven treatments with unproven products or practices.”

NCCIH (U.S. National Institutes of Health) — 6 Things To Know About ProbioticsPassage verified word-for-word in saved copy
38

Blood in the stool, or black, tarry stools — see a doctor right away.

“Contact your provider right away if:”
“You notice blood or changes in the color of your stool”

MedlinePlus (U.S. National Library of Medicine) — Black or tarry stoolsPassage verified word-for-word in saved copy
39

Blood in the stool, or black, tarry stools — see a doctor right away.

“If you have symptoms of acute or severe GI bleeding, seek medical help right away.”
“black or tarry stool”
“vomit that looks like coffee grounds”

NIDDK (U.S. National Institutes of Health) — Symptoms & Causes of GI BleedingPassage verified word-for-word in saved copy
40

Sudden, sharp belly pain, or a belly that is rigid and hard to touch — get medical help right away or call 911. Belly pain that is getting worse or not better after 24 to 48 hours — contact your provider.

“Get medical help right away or call 911 or the local emergency number if you:”
“Have sudden, sharp abdominal pain”
“Have tenderness in your belly, or your belly is rigid and hard to the touch”
“Contact your provider if you have:”
“Abdominal pain that does not improve in 24 to 48 hours, or becomes more severe and frequent and occurs with nausea and vomiting”

MedlinePlus (U.S. National Library of Medicine) — Abdominal painPassage verified word-for-word in saved copy
41

Diarrhea with fever, or diarrhea during or after antibiotics that won’t settle — call your provider right away.

“Also contact your provider right away if you have:”
“Blood or pus in your stools”
“Diarrhea with a fever above 101°F or 38.33°C (100.4°F or 38°C in children)”

MedlinePlus (U.S. National Library of Medicine) — DiarrheaPassage verified word-for-word in saved copy
42

Diarrhea with fever, or diarrhea during or after antibiotics that won’t settle — call your provider right away.

“Call your health care provider if you develop any side effects while taking your antibiotic.”

MedlinePlus (U.S. National Library of Medicine) — AntibioticsPassage verified word-for-word in saved copy
43

Signs of dehydration — very little urine, dizziness or confusion — get urgent care.

“Contact your provider right away if you or your child shows signs of dehydration:”
“Decreased urine (fewer wet diapers in infants)”
“Dizziness or lightheadedness”

MedlinePlus (U.S. National Library of Medicine) — DiarrheaPassage verified word-for-word in saved copy
44

Signs of dehydration — very little urine, dizziness or confusion — get urgent care.

“Signs of severe dehydration include:”
“Not urinating, or very dark yellow or amber-colored urine”
“Irritability or confusion”

MedlinePlus (U.S. National Library of Medicine) — DehydrationPassage verified word-for-word in saved copy
45

Unexplained weight loss, or a change in bowel habits lasting more than a few weeks — book an appointment this week.

“You have lost more than 10 pounds (4.5 kilograms) or 5% of your normal body weight over 6 to 12 months or less, and you do not know the reason.”

MedlinePlus (U.S. National Library of Medicine) — Weight loss - unintentionalPassage verified word-for-word in saved copy
46

Unexplained weight loss, or a change in bowel habits lasting more than a few weeks — book an appointment this week.

“If your bowel habits change, however, check with your provider.”

MedlinePlus (U.S. National Library of Medicine) — ConstipationPassage verified word-for-word in saved copy

Source documents

NIDDK (U.S. National Institutes of Health) — Your Digestive System & How It Works
Saved 2026-10-19 · download · SHA-256 095d7ef0bb4c5e3e…
NIEHS (U.S. National Institutes of Health) — Microbiome
Saved 2026-10-19 · download · SHA-256 04f5b5266349b048…
NCCIH (U.S. National Institutes of Health) — Probiotics: Usefulness and Safety
Saved 2026-10-19 · download · SHA-256 d046743729308a02…
NCCIH (U.S. National Institutes of Health) — 6 Things To Know About Probiotics
Saved 2026-10-19 · download · SHA-256 c0a5a8fb86f89fff…
NIH Office of Dietary Supplements — Probiotics - Fact Sheet for Consumers
Saved 2026-10-19 · download · SHA-256 bc79109dad3d8584…
MedlinePlus (U.S. National Library of Medicine) — Antibiotics
Saved 2026-10-19 · download · SHA-256 395f2ccb84059e74…
MedlinePlus (U.S. National Library of Medicine) — Fiber
Saved 2026-10-19 · download · SHA-256 2e0941cfb8d68ec1…
NCCIH (U.S. National Institutes of Health) — “Detoxes” and “Cleanses”: What You Need To Know
Saved 2026-10-19 · download · SHA-256 9af17cc04deffde4…
MedlinePlus (U.S. National Library of Medicine) — Black or tarry stools
Saved 2026-10-22 · download · SHA-256 8b07228011e06930…
NIDDK (U.S. National Institutes of Health) — Symptoms & Causes of GI Bleeding
Saved 2026-10-22 · download · SHA-256 f638d7347fec6fb3…
MedlinePlus (U.S. National Library of Medicine) — Abdominal pain
Saved 2026-10-22 · download · SHA-256 e1147d23d2af2bad…
MedlinePlus (U.S. National Library of Medicine) — Diarrhea
Saved 2026-10-22 · download · SHA-256 d5633490a57d2287…
MedlinePlus (U.S. National Library of Medicine) — Dehydration
Saved 2026-10-19 · download · SHA-256 0bf95dcc808c7c4b…
MedlinePlus (U.S. National Library of Medicine) — Weight loss - unintentional
Saved 2026-10-22 · download · SHA-256 70a05566ad916ffe…
MedlinePlus (U.S. National Library of Medicine) — Constipation
Saved 2026-10-22 · download · SHA-256 0f68cf9a9280eed8…

Historical perspective: Dr. Majid Ali archive

Historical perspective drawn from the authorized writings of Dr. Majid Ali, preserved in the Clarkson archive. Shown for context; it is not current medical guidance.

Health Is Rooted In Healthy Bowel Ecology – An Introduction 2015-03-28
Source of the quoted line and his "bowel ecology" framing. His claims that many unrelated chronic problems resolve when bowel ecology is restored are not carried.
When and Why Did I Introduce the Term Bowel Ecology? 2012-12-24
His own account of coining the term in the late 1970s and 1980s as a hospital pathologist. Used for dates only.

Claims we deliberately did not carry

Detox and colon-cleanse programmes described in bowel-ecology language.
Rejected, not held. No compelling research for detox diets, and colon cleansing can have serious side effects.³⁵³⁶
That restoring bowel ecology resolves fatigue, mood swings, joint pain, headaches, asthma and other unrelated problems.
Not established. Links between the microbiome and disease are still being researched.¹¹¹²
Bowel ecology as an explanation for autism, or as a way to eradicate specific infections.
Not supported by the sources used. Held in the pharmacist-review archive.
That food emulsifiers damage the gut lining.
Not covered by the saved sources. Held, not carried.
From the library brief: "most immune tissue sits along the gut wall" and "diet shifts gut bacteria within days".
Not found in any saved source. The page says only what NIEHS states: microbes help the immune system develop, and diet can change the microbiome over time.⁶⁸

Safety wording awaiting sign-off

The 'When to get help now' list is ProperHealth safety wording. Each line cites the official guidance it follows, and those passages are listed above with the other claims. The wording still needs pharmacist sign-off before public use.