Does Yakult Make You Poop? What You Need to Know

/ / Does Yakult Make You Poop? What You Need to Know

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Yakult is a popular probiotic beverage created in Japan and is sold in 39 nations and regions across the globe. With decades worth of bacteriological studies, it has gained global recognition for the use of friendly microbiota in foods, as well as pharmaceuticals and cosmetics.

Since Yakult is a well-recognized probiotic drink, you may wonder whether Yakult does make you poop and help you get or maintain a healthy bowel movement. Here’s what you need to know about Yakult and its effect on your digestive system.

Does Yakult Make You Poop?

Yakult contains an exclusive single live bacterial species called Lactobacillus casei Shirota. This bacterial strain is commonly found in commercially available probiotic drinks like yogurt beverages and is scientifically proven to make you poop, improve your digestion, and help you build immunity.

So how do these bacteria actually make you poop?

Read on to know more…

How Yakult makes you poop and improves your digestive system?

In order for you to truly understand how Yakult and the bacteria it contains make you want to poop, you first need to understand how your gut works.

While bacteria are typically thought to be harmful and make you ill, your body hosts two types of bacteria: the good and bad bacteria.

The good live bacteria that naturally reside in your body are called probiotics. Some probiotics are also created from good yeast.

Your small and large intestines are home to trillions of flourishing, living microorganisms called the gut flora. Some of these bacteria are harmful, while most of them not only live harmlessly in your digestive system but are also critical for your well-being. 

Apart from your gut, these beneficial microbes live in a few other places which are connected to the outside world, such as the mouth, lungs, skin, urinary tract, and vagina.

The main job of beneficial bacteria or probiotics is to maintain your body’s healthy balance. When you are ill, bad bacteria enters your body and increases in quantity, knocking your body out of balance.

You can also cause your digestive system to be out of balance if you consume an unbalanced diet, have too much stress, lack daily exercise, and lack sleep.

In such circumstances, you give the bad bacteria a chance to multiply and cause you to have a weak immune system and poor digestion.

This is where good bacteria comes in. They will fight off these harmful bacteria and try to restore your body’s balance so you can feel better again.

In addition, good bacteria improve your health by controlling inflammation and supporting your immune system.

One way you can increase the number of good bacteria in your body is by consuming foods, beverages, or supplements that contain probiotics. 

Drinking Yakult, which contains the exclusive probiotic L. casei Shirota, helps increase the amount of beneficial microbiota in your digestive system and prevent the harmful ones from taking over.

Yakult has a high amount of probiotics concentration with more than 6.5 billion L. casei Shirota in every bottle.

Lactobacillus casei is one of the various species that belongs to the Lactobacillus genus, one of the two particular types of bacteria typically found in grocery stores, another one being the Bifidobacterium. It has been officially recategorized to Lacticaseibacillus casei as of April 2020. 

Thus, the complete strain name of Lactobacillus casei Shirota can also be referred to as Lacticaseibacillus casei Shirota​. This particular bacterial strain has been studied extensively for its probiotic effect. It can withstand bile juice and gastric acid.

Nice to know: Lactobacillus casei has a small rod shape and is first discovered in cheese. Lactobacillus casei Shirota is named after Dr. Minoru Shirota who discovered and isolated the strain Shirota from over 300 lactic acid bacteria.

One randomized controlled trial published in the Applied and Environmental Microbiology journal found that consuming Yakult every day helps enhance digestion and build immunity.

Moreover, one survey released in the Journal of Neurogastroenterology and Motility found that Yakult significantly improved constipation symptoms. Particularly, Yakult improves stool quality. Patients with hard and watery stool successfully regain normal stool consistency after consuming Yakult.

Still, even though Yakult helps you poop, you should not treat it as a laxative.

The objective of probiotics is not to stimulate your bowels. Rather, they help regulate your bowel movements by improving your gut microbiota or the collection of beneficial bacteria in your gut.

You need to consume Yakult on a regular basis to see results.

Is Yakult good for your stomach?

Yakult is good for your stomach and can positively impact your digestive system. It contains the probiotic Lactobacillus casei Shirota, which helps increase the number of beneficial bacteria in the digestive tract, decreases the production of harmful toxins in the intestine, and regulates bowel movements.

Lactobacillus species, including L. casei Shirota and L. acidophilus, have been examined for their probiotic properties.

Particularly, Lactobacillus casei is one of the friendly living microorganisms that resides deep within your gut and treats your digestive system as its home.

As I’ve mentioned before, L. casei is beneficial for your digestive health and helps keep bad bacteria under control. In fact, your body relies on them to digest food and absorb essential nutrients. 

Other reported clinical effects associated with Lactobacillus consumption include:

  • Enhancement of the immune function
  • Lowering of fecal enzyme activity
  • Intestinal disorder prevention
  • Reduction of viral diarrhea

Researchers have been using Lactobacillus casei Shirota found in Yakult in many studies to evaluate its potential to preserve flora balance and potentially prevent diarrhea symptoms and gastrointestinal infection.

A study published in the Food and Agricultural Immunology journal found that Lactobacillus casei Shirota decreased the antibiotic-induced reduction in the abundance of total gut bacteria and Bifidobacterium in the placebo group. This bacterial strain’s intervention also increases Lactobacillus bacteria levels.

Another study released in the International Journal of Probiotics & Prebiotics suggested that the strain Lactobacillus casei Shirota helps decrease the recurrence of Clostridium difficile infection, which can result in symptoms ranging from diarrhea to fatal colon inflammation.

Moreover, findings in a 2011 Japanese study by Nagata et. al. indicated that patients who consumed a fermented drink containing L. casei Shirota had lowered fever symptoms compared to those that take a placebo. Remarkably, after two months of consumption, the levels of disease-causing bacterial groups Pseudomonas and Enterobacteriaceae decreased. 

Yakult’s L.casei Shirota was also trialed in an elderly group with norovirus gastroenteritis in a nursing home to determine if probiotics can help normalize bowel movements and enhance infection control.

The probiotic group showed a notable difference in intestinal bacteria, including a decrease in the quantity of destructive microbiota like Clostridium difficile, bowel movements improvement, and fever reduction.

A study published in the British Journal of Nutrition also found that continuous consumption of L.casei Shirota fermented milk could positively alleviate fever due to norovirus gastroenteritis by correcting the intestinal microflora imbalance distinctive to the elderly.

Does Yakult help constipation?

Since Yakult can make you poop, you probably wonder whether Yakult can help with constipation.

Yakult which contains L. casei Shirota can indeed help relieve symptoms of constipation, particularly if you have constipation due to irritable bowel syndrome.

Lactobacillus, the family that L. casei belongs to, is one of the most typical and extensively studied strains and has been used to treat digestive issues, including constipation. 

Various studies have also been conducted to assess the association between probiotic L.casei Shirota in Yakult and constipation.

Research from China found that the consumption of commercial fermented dairy beverages containing L. casei Shirota help normalizes stool consistency, increases the frequency of defecation, and relieves constipation-related symptoms in adults with constipation.

The researchers identified a non-volatile metabolite in the gut known as pipecolinic acid (PIPA) as the potential target mediator that helps alleviate the constipation symptoms.

L. casei Shirota strain was also assessed in a clinical trial involving 70 chronically constipated adults. This study is published in the Canadian Journal of Gastroenterology and Hepatology.

Each subject of the study had symptoms of constipation, bloating, and flatulence. Findings showed that up to 89% of the probiotic group who consumed probiotic drinks containing L.casei Shirota have improved stool consistency and constipation symptoms. The researchers recommend using probiotic foodstuffs as an adjective therapy for chronic constipation.

Another recent study published in the Journal of Neurogastroenterol and Motility also evaluated the differential effects of L.casei Shirota on stool consistency of patients with constipation in China.

The researchers found that L. casei Shirota normalized stool consistency: it softened hard stool and hardened soft stool. These effects could be related to the gut microbiota’s modulation and short-chain fatty acid production.

In addition, Yakult’s L.casei Shirota strain was trialed in a randomized study involving 120 adult patients with mild constipation. The patients were divided into two groups: one group was given a fermented milk beverage containing L.casei Shirota, while the other group was provided with a placebo drink. 

The results demonstrated that patients who have taken the probiotic drink have a significant improvement in stool consistency; their stool becomes softer and easier to pass. Viable L.casei Shirota was also found in their stool exams.

Can too much Yakult cause diarrhea?

According to the National Institutes of Health, probiotic supplements have an average dose of 1 to 10 billion CFUs or colony-forming units.

Most healthy adults can take around up to 20 billion CFUs of probiotics from supplements or foods every day. However, this figure is not absolute since each individual has a different microbiome.

Consuming too many probiotic foods or beverages like Yakult does not necessarily lead to positive results.

Rather, they may provoke certain mild, uncomfortable side effects, including diarrhea, bloating, and excess gas.

Some people also tend to have an upset stomach, mostly gas, when taking probiotics for the first time since their gut experiences some adjustment with regards to the bacterial levels.

However, these side effects will typically go away if they take an average dose and once their bodies have adjusted to the changes.

Nevertheless, people with severe diseases or have weak immune systems have a higher risk of experiencing adverse effects, such as an infection when consuming too many probiotics.

Therefore, if you fall into either of these high-risk groups, you should consult with your healthcare providers before taking any probiotics.


Yakult is good for your stomach and digestive function. It makes you poop and helps improve gastrointestinal symptoms, including constipation and diarrhea.

The main contributor to Yakult’s’ positive effect on your digestive system is the probiotic Lactobacillus casei strain Shirota.

One 65-mL bottle of Yakult contains over 6.5 billion L.casei Shirota.

Unlike other germs that make you ill, L. casei Shirota offers multiple benefits to your digestive function and overall well-being.

Some proven health benefits of Yakult’s exclusive probiotic L. casei Shirota include:

  • Increases the number of friendly bacteria in your gut to prevent the harmful ones from taking over
  • Normalizes stool consistency: it helps hardened soft stool and softened hard stool
  • Regulates bowel movement
  • Increases defecation frequency and relieves constipation-related symptoms
  • Lowers the recurrence of Clostridium difficile infection
  • Alleviates fever due to norovirus gastroenteritis

Consuming Yakult every day helps improve your digestion and build your immunity.

Is it okay to drink Yakult when you have diarrhea? 

Intestinal bacterial imbalance is one of the main causes of diarrhea. Thus, consuming probiotic drinks like Yakult which contain L.casei Shirota that helps restore the balance between bad and good bacteria in the gut can be helpful. Lactobacillus-containing supplements have also been used to treat digestive issues like diarrhea.

Can you drink Yakult on an empty stomach?

You can drink Yakult at any time of the day, even on an empty stomach. Studies conducted by the Yakult Central Institute found no significant difference when consuming Yakult 30 minutes before or after meals. Consistency is more important than the specified time of probiotic consumption.

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