Generic Name: Lactobacillus

Brand and Other Names: Lactobacillus acidophilus, Bacid, Culturelle

Drug Class: Herbals

What is lactobacillus, and what is it used for?

Lactobacillus refers to some of the species of bacteria that live within human digestive and genitourinary tracts and are essential for maintaining good health of these systems. The “good” bacteria including Lactobacillus species help the digestive system break down food and absorb nutrients and prevent the proliferation of infection-causing organisms in the digestive and genitourinary tracts.

Lactobacillus acidophilus is one of the most common species of bacteria used as a probiotic supplement. Lactobacillus supplements help restore normal bowel flora, inhibit the growth of disease-causing pathogens and improve local immunity. Lactobacillus controls diarrhea and facilitates proper stool formation by promoting water reabsorption in the colon.

Different formulations of lactobacillus supplements are available over the counter (OTC) and are taken orally to improve gut health, particularly after antibiotic use for infections. Antibiotics destroy the good bacteria along with the disease causing pathogens and the loss of gut flora can lead to impaired digestion and diarrhea. Lactobacillus suppositories and vaginal tablets are used to reduce bacterial overgrowth in the vagina. Yogurt is a natural source of lactobacillus.

The suggested uses of lactobacillus include:


  • Do not use lactobacillus in immunocompromised patients. Supplements with live bacteria may be associated with invasive fungal infection.
  • Do not use lactobacillus in patients with gastrointestinal perforation, the bacteria can get out of the bowel and may cause systemic infection.
  • Do not use lactobacillus if you are sensitive to soy or milk protein.
  • Use lactobacillus with caution if you are lactose intolerant.
  • Lactobacillus formulations differ in composition and biologic activity. Do not use different products interchangeably.

What are the side effects of lactobacillus?

Common side effects of lactobacillus include:

May cause infection in immunocompromised individuals.

Call your doctor immediately if you experience any of the following symptoms or serious side effects while using this drug:

  • Serious heart symptoms include fast or pounding heartbeats, fluttering in your chest, shortness of breath, and sudden dizziness;
  • Severe headache, confusion, slurred speech, severe weakness, vomiting, loss of coordination, feeling unsteady;
  • Severe nervous system reaction with very stiff muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, and feeling like you might pass out; or
  • Serious eye symptoms include blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights.

This is not a complete list of all side effects or adverse reactions that may occur from the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may also report side effects or health problems to the FDA at 1-800-FDA-1088.


Pancreatitis is inflammation of an organ in the abdomen called the pancreas. See Answer

What are the dosages of lactobacillus?



  • Lactobacillus: 1-2 capsules orally each day
  • 1-10 billion colony forming units (CFU) per day orally divided three to four times a day
  • 8 oz yogurt two times a day
  • Take at least 2 hours after antibiotic; continue for several days after antibiotic treatment is finished


  • Lactobacillus overdose is not expected to have any serious side effects. Overdose may cause flatulence and bloating which usually resolve upon discontinuation of lactobacillus.
  • Seek medical help or contact Poison Control if overdose symptoms do not resolve.

What drugs interact with lactobacillus?

Inform your doctor of all medications you are currently taking, who can advise you on any possible drug interactions. Never begin taking, suddenly discontinue, or change the dosage of any medication without your doctor’s recommendation.

  • Lactobacillus has no known severe, serious, moderate, or mild interactions with other drugs.

The drug interactions listed above are not all of the possible interactions or adverse effects. For more information on drug interactions, visit the RxList Drug Interaction Checker.

It is important to always tell your doctor, pharmacist, or health care provider of all prescription and over-the-counter medications you use, as well as the dosage for each, and keep a list of the information. Check with your doctor or health care provider if you have any questions about the medication.

Pregnancy and breastfeeding

  • Lactobacillus is likely safe when appropriately used during pregnancy and breastfeeding.
  • Check with your healthcare provider before taking any supplement including lactobacillus if you are pregnant or breastfeeding.

What else should I know about lactobacillus?

  • Lactobacillus supplements are generally safe for most people when appropriately used.
  • Take lactobacillus supplements exactly as per label instructions.
  • Lactobacillus supplements are marketed as dietary supplements and are not stringently regulated by the FDA. Products may differ in formulations and strengths; exercise caution in choosing your product.

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Medically Reviewed on 7/7/2022