NOTE: It is important to clear any use of supplements with your doctor. Some of them can interact with medications you might be taking or are anticoagulants. Some of them are not recommended to take while pregnant.
There are some herbs and supplements that potentially can be useful in helping with GI problems from surgery or from chemotherapy. Research is limited and most of them are more antecdotal than have good research support. Make sure you talk to your doctor before using any supplement.
1. Aloe Vera
It is known for helping soothe skin but it is also a powerful laxative. Aloe juice is made from the gel of the Aloe plant. The aloe juice may also contain citrus or other fruit juices, water, and preservatives. While aloe can be used as a laxative, it can irritate the digestive take and should only be taken for limited usage. It can cause electrolyte imbalances. Children and pregnant women should not take aloe internally.
2. Apple Cider Vinegar
Apple cider vinegar is often touted as a cure all for every thing. It is seen in Asian cultures to promote long life. However, research doesn’t bare out most things. It can help improve digestion and treat problems like indigestion, gas, bloating, stomachaches and heartburn. Apple cider vinegar contains acetic acid, vitamin C, and B vitamins. Acetic acid can increase the body’s absorption of important minerals from the foods we eat. It is a prebiotic. Prebiotics help to feed the gut bacteria and promote a health gut. However, apple cider vinegar has been shown to interact with laxatives and one study showed GI distress in people with diabetes.
How to take: Add to food, or drink a tablespoon in water. Vinegar added to baked goods improves yeasts ability to rise.
3. Asafetida
The potent-smelling and bitter tasting spice asafetida has been reported to be helpful for your digestive health due to its antispasmodic, anti-inflammatory, antioxidant and antiflatulent properties. Asafetida also has anticoagulant properties and should not be taken when on blood thinners. Also it will decrease healing post surgery.
How to use:
To improve digestion, mix a pinch of asafetida in a glass of warm water and drink it after your meals. Also, include this spice in your daily cooking.
4. Fennel
Fennel has long been popular in India as a digestive. It is common to chew fennel seek after meals to help with digestion. You can use them to treat heartburn, indigestion and low stomach acidity. These seeds also provide relief from intestinal spasms and bloating commonly associated with IBS. Studies show that the properties of fennel are due to volatile oil in the seed. The volatile oils are believed to stimulate bile which aids in the uptake of cholesterol. One study has sown there may be increase in flatulence. Studies have shown that fennel may increase estrogen. It is not recommended for pregnant women. Since some cancers are responsive to estrogen, it is important to discuss use fennel with your doctor prior to use.
How use:
Chew 1 teaspoon of fennel seeds after eating your meal to aid digestion.
Fennel tea: To make fennel tea, steep 1 teaspoon of crushed fennel seeds in a cup of hot water for about 5 minutes.
Fennel seed powder: Mix ½ teaspoon in glass of water twice daily.
5. Ginger
Ginger is rhizome (root). It has an intensely zesty flavor. It is found from Asian cuisines to Gingerbread. It is a very versatile flavor. It has been used for thousands of years for both culinary use and herbal medicine. Ginger can stimulate your digestive juices and the flow of enzymes needed to properly digest food. It is effective for preventing and reducing nausea, vomiting, flatulence, indigestion, bloating and diarrhea.
Ginger also has some antiseptic properties. It has been suggested for infection of the digestive tract. Ginger has some antiplatelet activity and needs to be used with caution with blood thinners or prior to surgery. See the NIH article for more information on ginger.
According to Dr. Andrew Weil, he recommends the following:
Inflammation: 2-3 grams of powdered ginger per day in divided doses.
Nausea: 1 gram for prevention and 500 grams for maintenance.
Do not use more than 1000 grams per day.
How to use:
Tea: Drink 2 to 3 cups of ginger tea daily. boil 1 teaspoon of freshly grated ginger in 1½ cup of hot water. Let it simmer for 10 minutes, strain out the ginger, add some raw honey and enjoy your tea. Provides about 250 mg of ginger per cup.
Whole/Slice: chew a small piece of ginger after your meals.
Ginger piece: 1/4 inch piece has about 500 mg of ginger.
Crystallized ginger candy will have about 500mg of ginger per candy.
Ginger ale: if drinking ginger ale made with real ginger will have about 1 gram of ginger per 8 ounce cup.
Ginger capsule come in 100 and 200mg capsules.
Ginger powder:1 tablespoon powdered ginger equals 5.20 grams
6. Magnesium
Magnesium is an essential mineral that is needed for functioning in all organs. It helps with constipation in two ways. First it helps to draw water into the colon to help soften stools. It also stimulates the muscles in the digestive tract.
Avoid taking tetracycline/quinolone antibiotics (e.g., doxycycline, tetracycline, ciprofloxacin) within 2 hours before or after this product. Doing so may decrease the effect of the antibiotic.
Talk to your doctor if you have a heart, kidney or intestinal disease, high blood pressure ore are pregnant or plan to breast feed.
Over use of magnesium causes diarrhea cramping and allergic reactions.
How to use:
Food: tofu, molasses, pumpkin seeds, leafy green vegetables, black beans, almonds, cashews, potatoes, avocados, bananas, broccoli, brussel sprouts, and cocoa powder.
Magnesium citrate: liquid that can be mixed in water. Drink a full glass of water with this.
Magnesium hydroxide (Milk of Magnesia MOM): use as directed
Magnesium pills:
According to NIH:
Infants–6 months: 30 mg
7–12 months: 75 mg
1–3 years: 80 mg
4–8 years: 130 mg
9–13 years: 240 mg
14–18 years: 410 mg for men; 360 mg for women
19–30 years: 400 mg for men; 310 mg for women
Adults 31 years and older: 420 mg for men; 320 mg for women
Pregnant women: 350-360 mg
Women who are breastfeeding: 310-320 mg
7. Peppermint
Its carminative, antispasmodic and anti-inflammatory properties help treat gas, bloating, intestinal cramps as well as nausea and vomiting. There have been some studies with peppermint oil for its antispasmodic ability and digestive benefits.
Studies have not been done on peppermint leaf. Peppermint should not be used near the face or near soft tissues.
8.Probiotics
Probiotics line the digestive tract. They help with absorption of nutrients. They also boost our immune system. Gut bacteria is also important in producing Vitamins K2 and B12 and stimulate secretion of IgA and T-cells which are involved in the immune system. Probiotics can be found in kefir, kombucha and fermented foods like sauerkraut. Yogurt is a prebiotic bacteria which helps to feed the bacteria and improve probiotics ability to work. Other things you can use to feed probiotics are high fiber foods, fruits and vegetables, sweet potatoes.
Probiotics can also be taken as a supplement. However, food sources of probiotics have a much higher level of probiotic bacteria than supplements do and therefore are more effective.
9. Psyllium Husks
Psyllium husks or powered come from the plant Plantago psyllium. This natural laxative contains insoluble fiber that adds bulk to your stool and makes bowel movements easier. Psyllium husks also bind to fatty acids and cholesterol.
How to use:
– mix 1/2 – 1 tsp in a glass of water
Psyllium husks can also be used in gluten free baking as a placement for Xanthum Gum in an 1:1 exchange. However, it is difficult to find in the baking section and is usually found in pharmacy section for digestive aids.
10. Rhubarb Root 
Rhubarb (Rheum offidnale or Rhuem Palmatum) is a hardy perennial that is native to the cool mountains and high plateaus of western China and Tibet. The more common rhubarb (Rheum rhabarbarum) that is used for food does not have any medicinal use. Medicinal rhubarb contains anthraquinone glycosides (laxative), tannins (astringents), a bitter principle, pectin, rutin, starch, catechin, phytosterol, gallic acid
This is one of the safest and least violent irritant laxatives, but it should be reserved for occasional use only. However, it should not be used by pregnant women or children under the age of 12. Rhubarb leaves are poisonous and should never be eaten.