How do you solve a problem like diarrhea? Dietitian Sandra Mikhail details the tests you need to know about for a troublesome tum and what you can do now to ease symptoms fast.
Diarrhea has no consideration of place and time. I had one of the worst poop experiences of my life on a moving train in Egypt on the way to see the pyramids, after eating a cheese sandwich from the coffee cart. The toilet was a hole in the floor, and I had the man I was dating manning the door and asking whether I needed support to “balance” myself.
The type of diarrhea I experienced is known as acute, usually defined as three or more loose or watery stools per day, lasting less than four weeks. This tends to be the most common form and is mainly infectious in nature, meaning you’ve possibly contracted a bacterial, viral or parasitic infection. We’ve all heard of the “stomach flu,” also known as viral gastroenteritis, and that tends to be one of the most common causes.
If diarrhea persists, there’s a chance you may be dealing with something more than just an acute bout of loose poo. It’s classed as chronic if it lasts longer than four weeks, and working out the cause is much more complex. A long list of underlying issues and conditions need to be ruled out.
Here’s a guide to the investigations to perform and possible causes to consider if you suffer from chronic diarrhea, as well as what you can do to ease those tummy troubles straightaway.
There are several tests I generally recommend as an investigative starting point.
Depending on the results, a colonoscopy (when a camera is used to look inside your rectum and colon) may be warranted. Keep in mind that although some conditions can seem scary when learning about what they are, more often than not, the cause of chronic diarrhea is manageable and is not life-threatening.
Some of the potential causes include:
Diarrhea can also be a side-effect of some medications, such as:
Symptoms of irritable bowel syndrome (IBS), which include bloating, abdominal pain or discomfort, flatulence, diarrhea and/or constipation, are similar to those experienced by people with small intestinal bacterial overgrowth, or SIBO.
What is SIBO?
SIBO is diagnosed when there are excessive numbers of bacteria in the small intestine. In a healthy digestive system, the number of gut bacteria in the small intestine is quite low, so when the number is excessive, it is often the result of an anatomical abnormality or digestive illness.
The most common conventional causes are related to motility disorders (i.e., conditions that slow movement of food through the small intestine); structural problems present along the small intestine, such as adhesions; or medical conditions that can impact the motility of food in the small intestine, such as Crohn’s disease and diabetes.
Anywhere from 4 to 78 percent of patients with IBS also have SIBO. That’s a pretty wide gap. But this is because the medical community hasn’t yet landed on one standardized test for diagnosing SIBO.
Most cases are diagnosed through one of two types of hydrogen breath testing: the lactulose breath test (LBT) or the glucose breath test (GBT). Both tests measure concentrations of hydrogen and methane in the breath.
If your doctor prescribes this test, you will be asked to drink a sugar solution and then provide samples of your breath at various intervals. If hydrogen and/or methane is detected within 90 minutes, SIBO will be diagnosed.
The length of time is key—generally it would take two hours for the sugar solution to make its way to the large intestine, so any rise in these gases prior to that time suggests that the sugar was acted on by bacteria in the small intestine.
This method has considerable diagnostic limitations: it lacks sensitivity and specificity, which means there is a high chance of getting a false positive or false negative result.
The best method of diagnosing SIBO is sampling fluid from the small intestine and growing the bacteria found in this fluid to estimate whether a very high number of bacteria are present. Because it is an invasive procedure, it is rarely used in clinical practice unless a gastroenterologist thinks it’s necessary.
Oregano for SIBO
If you’ve been diagnosed with SIBO, the main treatment is a certain type of antibiotic, one that is not absorbed in the stomach and therefore can make its way to the small intestine, where it can eliminate any bacteria it finds there. The most common one is rifaximin, aka Xifaxan.
But a great alternative is oregano oil, a natural antibiotic with the active ingredients thymol and carvacrol. Carvacrol fights against a variety of bacterial strains, while thymol acts as an anti-inflammatory agent in addition to its antibacterial, antiviral and antifungal effects.
Clarify with your gastroenterologist or dietitian that this approach would work for you. The protocol I use is a 180–200 mg oregano oil capsule, three times per day with meals for three to six weeks.
A lot of the time, the cause of chronic diarrhea is food related, and simple dietary changes can have a big impact. These possible causes include IBS, which can be helped with a low-FODMAP diet (reducing the amount of fermentable sugars in your diet); lactose intolerance, which can be resolved with a low-lactose or lactose-free diet; celiac disease (an abnormal immune system rection to gluten), which can be controlled by eliminating gluten from the diet; and bile acid malabsorption (BAM), which can be helped by limiting fat in the diet.
While management of chronic diarrhea depends on the cause, whether food related or otherwise, there are four simple steps that are important for anyone suffering from diarrhea.
Step 1. Rehydration
The first line of therapy will always be correcting any electrolyte and fluid losses. Make fluid your best friend for the next 24 hours. The aim is to drink 2–2.5 L per day.
It is always best to have some oral rehydration solution (ORS) in your home pharmacy cabinet. ORSs are commonly bought as sachets or tablets and contain a mix of glucose, sodium and potassium to prevent dehydration. But you can easily make your own at home. Sip on this throughout the day.
Other beneficial fluid choices include bottled water, broth, diluted juice and sports drinks that contain salts such as sodium and potassium. However, it is best to avoid beverages such as sodas, fruit smoothies and milk-based beverages as they can make your
diarrhea more severe.
Watch out for these signs of dehydration: being thirsty, having dark-colored urine, urinating less than normal, feeling extremely tired and feeling dizzy. If you have any of these symptoms, you’ll need to drink more.
DIY rehydration solution
Here’s what the World Health Organization recommends for a 1-L rehydration solution using household measuring spoons for the quantities:
Step 2. Eat easy-to-tolerate foods
If your diarrhea and stomach cramps have settled, you’re probably ready for some real food, but naturally you won’t be rushing toward a creamy mushroom risotto or seafood chowder.
Start by including easy-to-tolerate foods that aren’t too high in fiber; that doesn’t mean, however, you should be eliminating fiber completely. As your diarrhea eases, the goal is to temporarily reduce the amount of insoluble fiber you are consuming until your stool is better formed. That means you can still have soluble sources of fiber.
We have moved beyond the outdated approach of BRAT—bananas, rice, applesauce and toast—which lacks any scientific backing yet was widely recommended by pediatricians and doctors to temporarily ease diarrhea. See the box on page 51 for a basic guide to foods you might tolerate well as you manage diarrhea.
Step 3. Limit foods known to worsen symptoms
Some foods are known to worsen diarrhea because they can cause more gas, bloating and loose stools by causing food to move through your gut too quickly. While diarrhea persists, it may be useful to avoid the following:
Step 4. Supplement wisely
When it comes to easing diarrhea with supplements, you may find psyllium husk and the probiotic strains listed below are helpful.
Psyllium husk is often used to resolve constipation, but you can also use it to manage diarrhea thanks to its water-holding capacity in your bowel that bulks up watery, loose stools.
Suggested dosage: Day 1, start with 1⁄2 tsp in a glass of water (250 mL), then wash that down with another glass. Day 2, increase the amount to 1 tsp in a glass of water and wash it down with another glass
Lactobacillus rhamnosus GG (LGG) is a probiotic strain that is used to treat and prevent antibiotic-associated diarrhea and traveler’s diarrhea.
Suggested dosage: You can take this strain two hours after breakfast and dinner at 5–6 billion CFU, twice a day for the duration of your antibiotic course and for one week after
Saccharomyces boulardii lyo CNCM I-745 is a probiotic yeast that has also been used to prevent both antibiotic-associated diarrhea and traveler’s diarrhea.
Suggested dosage: It is commonly sold in sachets of 10 billion CFU; follow the instructions on the label
Enteroccocus faecium SF68 is a strain commonly found in Europe that I have used with my clients for both the prevention and treatment of any infectious type of diarrhea.
Suggested dosage: For diarrhea prevention, take two capsules daily for two weeks. For treatment, take three capsules daily for the first week, then reduce to two capsules by the second week
After a case of diarrhea, your appetite may not be the greatest, and the focus should be on rehydrating and gradually gaining your strength and energy through food as your appetite returns. The following recipe suggestions are best kept for when you are ready to introduce food, keeping insoluble fiber to a minimum.
Ingredients (serves 4)
Toppings: Any fruit that you can tolerate
Ingredients (serves 4)
Breads, grains and cereals
(temporarily opt for well-cooked instead of raw)
(no more than two servings per day)
Meat and alternatives
(avoid tough, gristly meat)
Dairy and alternatives
(temporarily choose lactose-free options)
Adapted from The Gut Chronicles by Sandra Mikhail (Hammersmith Health Books, 2023)