Overview
Probiotics (Lactobacillus) are live microorganisms that provide health benefits when consumed in adequate amounts. They are frequently used to restore the natural balance of gut flora, especially during or after a course of antibiotics or following an episode of diarrhoea.

Mechanism of Action
They work by colonizing the gastrointestinal tract, competing with pathogenic bacteria for nutrients and adhesion sites on the intestinal wall. They also help maintain the integrity of the gut barrier and modulate the local immune response.

Dosage and Administration
Dosage varies widely depending on the specific strain and the product formulation. They are typically taken orally, 1 to 2 times daily. It is often recommended to take them at least 2 hours apart from antibiotic doses.

Side Effects
Probiotics are generally safe for most healthy individuals. Mild digestive symptoms such as gas, bloating, or minor stomach upset may occur initially but usually resolve with continued use.

Contraindications
They should be used with extreme caution or avoided in severely immunocompromised patients, premature infants, or individuals with short bowel syndrome, due to a rare but serious risk of systemic infection (bacteremia).