If lactose intolerance is the cause of diarrhea, supplemental use of lactase prior to consuming milk or milk-containing products can be helpful.¹²Cheese rarely has enough lactose to cause symptoms in lactose-intolerant people. Lactase products are available that can be chewed while drinking milk or added to milk directly.

The malabsorption problems that develop during diarrhea can lead to deficiencies of many vitamins and minerals.¹³ For this reason, it makes sense for people with diarrhea to take a multivitamin-mineral supplement. Two of the nutrients that may not be absorbed efficiently as a result of diarrhea are zinc and vitamin A, both needed to fight infections. In third world countries, supplementation with zinc and vitamin A has led to a reduction in, or prevention of, infectious diarrhea in children.¹⁴ There is evidence that even children who are not zinc-deficient could benefit from zinc supplementation during an episode of infectious diarrhea, if the diarrhea is being caused by certain specific organisms, such as the organism that causes cholera or some strains of E. coli.¹⁵

Colostrum might be useful for certain types of infectious diarrhea. In a double-blind trial, children with diarrhea caused by a rotavirus were treated with immunoglobulins extracted from colostrum derived from cows immunized with rotavirus. Compared with the placebo, colostrum extract significantly reduced the amount of diarrhea and the amount of oral rehydration solution required. The rotavirus was eliminated from the stool significantly more rapidly in the colostrum group than in the placebo group (1.5 days, vs. 2.9 days).¹⁶

In addition to a positive effect against acute rotavirus diarrhea,¹⁷ there is also evidence that specific forms of colostrum (derived from specially immunized cows or those with confirmed presence of specific antibodies) are effective against diarrhea caused by Cryptosporidium parvum, Helicobacter pylori, Escherichia coli, and Clostridium difficile.^{18 , 19 , 20 , 21 , 22} However, it is not known whether commercially-available colostrum provides significant amounts of the specific immunoglobulins that are active against these organisms. Furthermore, unless the immunoglobulins are present in high enough concentrations, the preparation is not likely to be effective.²³

Carob is rich in tannins that have an astringent or binding effect on the mucous membranes of the intestinal tract. A double-blind trial has suggested it may be particularly useful for young children and infants with diarrhea.²⁴ Some healthcare professionals recommend 15 grams of carob powder is mixed with applesauce (for flavor) when given to children. Carob can also be used for treating adult diarrhea.

While fiber from dietary or herbal sources is often useful for constipation, it may also play a role in alleviating diarrhea.

Some autistic children suffer from chronic diarrhea. In a study of children with autistic spectrum disorders and persistent diarrhea for many years, supplementing with 500 mg of glucosamine per day (spread over the morning and evening meal) for 30 days eliminated the diarrhea in five of six cases.²⁵ The authors hypothesized that glucosamine worked by blocking the effect of certain dietary components on the intestinal tract.

In a double-blind study of children (ages six months to two years) with acute diarrhea, supplementing with glutamine significantly reduced the duration of diarrhea by 26%.²⁶ Children were given 136 mg of glutamine per pound of body weight per day for seven days. Glutamine appeared to work by improving the health of the intestinal lining, rather than through any effect on the immune system.

While fiber from dietary or herbal sources is often useful for constipation, it may also play a role in alleviating diarrhea. For example, 9–30 grams per day of psyllium seed (an excellent source of fiber) makes stool more solid and can help resolve symptoms of non-infectious diarrhea.²⁷ Alginic acid, one of the major constituents in bladderwrack(Fucus vesiculosus), is a type of dietary fiber and as a result may potentially help relieve diarrhea. However, human studies have not been done on how effective bladderwrack is for this condition.

An extract from stem bark latex of Sangre de drago (Croton lechleri), an herb from the Amazon basin of Peru, has demonstrated significant anti-diarrheal activity in preliminary^{28 , 29} and double-blind trials. Double-blind research has demonstrated the extract’s effectiveness for traveler’s diarrhea,³⁰ non-specific diarrhea,³¹ and diarrhea associated with HIV infection and AIDS.^{32 , 33} For traveler’s diarrhea and nonspecific diarrhea, amounts ranging from 125 mg to 500 mg taken four times daily for two days have proven effective. However, in one trial, only the 125 mg four times daily amount (but not higher amounts) was effective for acute nonspecific diarrhea.³⁴ The reasons for the failure of higher amounts in this study is not known. Very high amounts of these extracts (350–700 mg four times daily for seven or more days) were used in the trials involving people with HIV and AIDS. Such levels of supplementation should always be supervised by a doctor. Most of this research on Sangre de Drago is unpublished, and much of it is derived from manufacturers of the formula. Further double-blind trials, published in medical journals, are needed to confirm the efficacy reported in these studies.

An extract from stem bark latex of Sangre de Drago (Croton lechleri), an herb from the Amazon basin of Peru, has demonstrated significant anti-diarrheal activity in preliminary³⁵ and double-blind trials. Additional double-blind research has demonstrated the extract’s effectiveness for diarrhea associated with HIV infection and AIDS.^{36 , 37} Very high amounts of this extract (350–700 mg four times daily for seven or more days) were used in the studies. Such levels of supplementation should always be supervised by a doctor. Most of this research on Sangre de Drago is unpublished, and much of it is derived from manufacturers of the formula. Further double-blind trials, published in peer-reviewed medical journals, are needed to confirm the efficacy reported in these studies.

Tormentil root (Potentilla tormentilla) is an herb that has been used for many years in different European folk medicines for the treatment of diarrhea. In a double-blind study of children with diarrhea caused by rotavirus infection, the duration of diarrhea averaged three days in children who received tormentil root extract, compared with five days in those who received a placebo.³⁸ No adverse effects were seen. The amount of tormentil root extract used was 3 drops for every year of life, taken three times a day until diarrhea stopped, or for a maximum of five days.

Due to of its supposed antimicrobial activity, goldenseal has a long history of use for infectious diarrhea. Its major alkaloid, berberine (also found in barberry and Oregon grape), has been shown to improve infectious diarrhea in some double-blind trials.³⁹ Negative studies have generally focused on people with cholera, while positive studies investigated viral diarrhea or diarrhea due to strains of E. coli. These studies generally used 400–500 mg berberine one to three times per day. Because of the low amount of berberine in most goldenseal products, it is unclear how effective the whole root or root extracts would be in treating diarrhea.

Astringent herbs traditionally used for diarrhea include blackberry leaves, blackberry root bark, blueberry leaves, and red raspberry leaves.⁴⁰ Raspberry leaves are high in tannins and, like blackberry, may relieve acute diarrhea. A close cousin of the blueberry, bilberry, has been used traditionally in Germany for adults and children with diarrhea.⁴¹ Only dried berries or juice should be used—fresh berries may worsen diarrhea.

Cranesbill has been used by several of the indigenous tribes of North America to treat diarrhea. The tannins in cranesbill likely account for the anti-diarrheal activity⁴²—although there has been little scientific research to clarify cranesbill’s constituents and actions.

Astringent herbs traditionally used for diarrhea include blackberry leaves, blackberry root bark, blueberry leaves, and red raspberry leaves.⁴³ Raspberry leaves are high in tannins and, like blackberry, may relieve acute diarrhea. A close cousin of the blueberry, bilberry, has been used traditionally in Germany for adults and children with diarrhea.⁴⁴ Only dried berries or juice should be used—fresh berries may worsen diarrhea.

Cranesbill has been used by several of the indigenous tribes of North America to treat diarrhea. The tannins in cranesbill likely account for the anti-diarrheal activity⁴⁵—although there has been little scientific research to clarify cranesbill’s constituents and actions.

While fiber from dietary or herbal sources is often useful for constipation, it may also play a role in alleviating diarrhea. For example, 9–30 grams per day of psyllium seed (an excellent source of fiber) makes stool more solid and can help resolve symptoms of non-infectious diarrhea.⁴⁶ Alginic acid, one of the major constituents in bladderwrack(Fucus vesiculosus), is a type of dietary fiber and as a result may potentially help relieve diarrhea. However, human studies have not been done on how effective bladderwrack is for this condition.

Astringent herbs traditionally used for diarrhea include blackberry leaves, blackberry root bark, blueberry leaves, and red raspberry leaves.⁴⁷ Raspberry leaves are high in tannins and, like blackberry, may relieve acute diarrhea. A close cousin of the blueberry, bilberry, has been used traditionally in Germany for adults and children with diarrhea.⁴⁸ Only dried berries or juice should be used—fresh berries may worsen diarrhea.

Cranesbill has been used by several of the indigenous tribes of North America to treat diarrhea. The tannins in cranesbill likely account for the anti-diarrheal activity⁴⁹—although there has been little scientific research to clarify cranesbill’s constituents and actions.

Chamomile may reduce intestinal cramping and ease the irritation and inflammation associated with diarrhea, according to test tube studies.⁵⁰ Chamomile is typically taken as a tea. Many doctors recommend dissolving 2–3 grams of powdered chamomile or adding 3–5 ml of a chamomile liquid extract to hot water and drinking it three or more times per day, between meals. Two to three teaspoons (10–15 grams) of the dried flowers can be steeped in a cup of hot water, covered, for ten to fifteen minutes as well.

Cranesbill has been used by several of the indigenous tribes of North America to treat diarrhea. The tannins in cranesbill likely account for the anti-diarrheal activity⁵¹—although there has been little scientific research to clarify cranesbill’s constituents and actions.

Acute diarrhea can damage the lining of the intestine. Folic acid can help repair this damage. In one preliminary trial, supplementing with very large amounts of folic acid (5 mg three times per day for several days) shortened the duration of acute infectious diarrhea by 42%.⁵² However, a double-blind trial failed to show any positive effect with the same level of folic acid.⁵³ Therefore, evidence that high levels of folic acid supplementation will help people with infectious diarrhea remains weak.

Due to of its supposed antimicrobial activity, goldenseal has a long history of use for infectious diarrhea. Its major alkaloid, berberine (also found in barberry and Oregon grape), has been shown to improve infectious diarrhea in some double-blind trials.⁵⁴ Negative studies have generally focused on people with cholera, while positive studies investigated viral diarrhea or diarrhea due to strains of E. coli. These studies generally used 400–500 mg berberine one to three times per day. Because of the low amount of berberine in most goldenseal products, it is unclear how effective the whole root or root extracts would be in treating diarrhea.

Herbs high in mucilage, such as marshmallow or slippery elm, may help reduce the irritation to the walls of the intestinal tract that can occur with diarrhea. A usual amount taken is 1,000 mg of marshmallow extract, capsules, or tablets three times per day. Marshmallow may also be taken as a tincture in the amount of 5–15 ml three times daily.

In laboratory experiments, a tannin in oak, known as ellagitannin, inhibited intestinal secretion,⁵⁵ which may help resolve diarrhea. Oak is well regarded in Germany, where it is recommended (along with plenty of electrolyte-containing fluids) to treat mild, acute diarrhea in children.⁵⁶

Due to of its supposed antimicrobial activity, goldenseal has a long history of use for infectious diarrhea. Its major alkaloid, berberine (also found in barberry and Oregon grape), has been shown to improve infectious diarrhea in some double-blind trials.⁵⁷ Negative studies have generally focused on people with cholera, while positive studies investigated viral diarrhea or diarrhea due to strains of E. coli. These studies generally used 400–500 mg berberine one to three times per day. Because of the low amount of berberine in most goldenseal products, it is unclear how effective the whole root or root extracts would be in treating diarrhea.

Astringent herbs traditionally used for diarrhea include blackberry leaves, blackberry root bark, blueberry leaves, and red raspberry leaves.⁵⁸ Raspberry leaves are high in tannins and, like blackberry, may relieve acute diarrhea. A close cousin of the blueberry, bilberry, has been used traditionally in Germany for adults and children with diarrhea.⁵⁹ Only dried berries or juice should be used—fresh berries may worsen diarrhea.

Cranesbill has been used by several of the indigenous tribes of North America to treat diarrhea. The tannins in cranesbill likely account for the anti-diarrheal activity⁶⁰—although there has been little scientific research to clarify cranesbill’s constituents and actions.

Sweet annie has been used traditionally to treat infectious diarrhea and malaria. However, more modern studies have used the isolated constituent artemisinin and it is unclear how effective the herb is in managing diarrhea.

Tylophora has been used traditionally in the Ayurvedic system for diarrhea probably due to its anti-inflammatory and antimicrobial actions, although human studies have not confirmed this use.

It is known vitamin A supplements support immune function and prevent infections. This is true, however, only under some circumstances. Vitamin A supplementation can also increase the risk of infections, according to the findings of a double-blind trial.⁶¹ In a study of African children between six months and five years old, a 44% reduction in the risk of severe diarrhea was seen in those children given four 100,000–200,000 IU supplements of vitamin A (the lower amount for those less than a year old) during an eight-month period. On further investigation, the researchers discovered that the reduction in diarrhea occurred only in children who were very malnourished. For children who were not starving, vitamin A supplementation actually increased the risk of diarrhea compared with the placebo group. The vitamin A-supplemented children also had a 67% increased risk of coughing and rapid breathing, and signs of further lung infection, although this problem did not appear in children infected with the AIDS virus. These findings should be of concern to American parents, whose children are not usually infected with HIV or severely malnourished. Such relatively healthy children fared poorly in the African trial in terms of both the risk of diarrhea and the risk of continued lung problems. Vitamin A provided no benefit to the well-nourished kids. Therefore, it makes sense not to give vitamin A supplements to children unless there is a special reason to do so, such as the presence of a condition causing malabsorption (e.g., celiac disease).