Bacteria are everywhere, and you have probably given them very little thought unless you’ve had a health issue that brought them into focus, such as antibiotic-associated diarrhea. Additionally, your gut is filled with bacteria, both good and bad, that help regulate your digestive system and are responsible for a great deal of immune functions. Lactobacillus casei is bacteria that help with our digestive system. The following is information about these helpful bacteria and how taking this supplement can benefit you.
What Is Lactobacillus Casei?
Lactobacillus casei is a bacteria that is found in a variety of places within the body, most notably the digestive tract. It may also be found in the urinary and genital tracts, as well. When you examine bacteria such as Lactobacillus casei, you find a host of different benefits to the body. However, certain bacteria are classified as probiotics. These bacteria include Bifidobacterium casei, Bifidobacterium bifidum, and Lactobacillus acidophilus. They help maintain a strict balance within the body, particularly the GI tract.
Lactobacillus casei is a very effective probiotic. It helps with nutrient absorption, as well as producing vitamins such as B vitamins. A common strain is Lactobacillus casei Shirota, which has been examined in a variety of studies.
You can find Lactobacillus casei in different environments, including in fermented plant products. The Lactobacillus casei gram stains positive and is a non-motile bacteria. It is also non-spore-forming and has a rod shape when examined under the microscope.
Lactobacillus Casei Benefits and Uses
The most common use of L. casei is to treat or prevent cases of diarrhea, including traveler’s diarrhea and stress-related diarrhea. Potential gastrointestinal issues that may respond to L. casei include constipation, ulcerative colitis, and Crohn’s disease. It may also be helpful in controlling inflammatory or immune conditions, such as allergies, acne, and cold or flu symptoms.
In certain studies, L. casei probiotic drinks were evaluated to see if they had certain effects on the GI tract. In one 2007 study, it was linked to a reduction in cases of antibiotic-associated diarrhea. In another study, it was used as part of a treatment protocol for people with chronic constipation successfully.
One particular study looked at people with Parkinson’s disease. Subjects in the test group who regularly consumed milk fermented with Lactobacillus casei Shirota had better regulation of their constipation than people who did not consume the probiotic.
Women with rheumatoid arthritis also benefited from consuming L. casei probiotics. A study showed that women taking probiotic supplementation had fewer rheumatoid arthritis symptoms and also had a decrease in their body’s production of inflammatory cytokines.
Lactobacillus casei Shirota has also been shown to improve symptoms of anxiety. In one study, an animal model was pre-treated with this probiotic before being exposed to stressful stimuli. Humans have also been examined. In those taking the probiotic, there were significantly lower salivary levels of cortisol, a stress hormone. People and animals taking the Lactobacillus casei Shirota for anxiety also had decreased physical symptoms of stress.
Lactobacillus Casei Dosage
There is no set dosage for Lactobacillus casei. People interested in taking it should contact their physician about their target dosage, particularly if attempting to treat a particular disorder. Most dosage guidelines suggest consuming 1 to 10 billion organisms or colony-forming units, divided into several dosages during the day. This probiotic is commonly found in combination with other probiotics.
Example treatments that have been studied with Lactobacillus species include treating for hay fever. For this, at least 2 billion colony forming units are taken twice daily for at least 7 weeks, generally in combination with an antihistamine.
For people being treated with chemotherapy, probiotics with Lactobacillus are sometimes used (although this should be directed by your physician). Typical treatments include taking 5 to 10 billion colony forming units twice daily while on chemotherapy to prevent diarrhea.
For people suffering from chronic constipation, Lactobacillus can be an effective treatment option. General guidelines are to take 200 to 400 million colony-forming units daily for 4 to 8 weeks. Some people make benefit from taking a higher target amount, 5 billion colony forming units, twice per day for 7 days, as well.

Forms of Lactobacillus Casei
Lactobacillus casei can be found in many different forms. First, it can be found in foods, including certain cheeses and fermented plant products. You can also get Lactobacillus casei yogurt and yogurt-like fermented milk.
Of course, Lactobacillus casei supplements are generally probiotic supplements. These are typically found in capsule forms, and it may be found in multi-species forms or single species bacterial forms. That means you may get Lactobacillus casei in a product by itself or find a product that includes other probiotics, such as Bifidobacterium bifidum.
Side Effects of Lactobacillus Casei
The good news is that Lactobacillus casei Shirota side effects are few and far between. Most people can take probiotics without noting any side effects, but the most common ones are mild gas from the bacteria working in the gastrointestinal tract. If you notice cramping or gas, you can try taking a lower dosage of the Lactobacillus casei product.
Unfortunately, there are rare cases of dangerous side effects from probiotics, such as systemic infections. If you have a weakened immune system, such as being on chemotherapy, it is vital that you speak to your physician before you start taking a probiotic.
Things to Keep in Mind When Using Lactobacillus Casei
As with any product, you will want to follow the guidelines on the label for your probiotic supplementation. This is even more important than with something such as aspirin because the probiotic product contains live organisms. Allowing the product to get too hot or humid can adversely affect the product’s viability. Expiration dates are also very important for these products.
There is little in the way of long-term data on the safety and efficacy of probiotic supplementation. While more studies are needed, there does not appear to be a problem for most people with taking a probiotic long term.
In Summary
Lactobacillus casei is a bacteria found in foods and many probiotic supplements. It is helpful at breaking down foods and helping the body produce nutrients such as B vitamins. It has also been linked to better break down and absorption of milk products. There are a variety of health conditions that respond well to L. casei, such as anxiety and constipation.
These statements have not been evaluated by the Food and Drug Administration. Products discussed are not intended to diagnose, treat, cure, or prevent any disease.