Doctors and natural healers alike may recommend probiotics, which are beneficial bacteria that promote intestinal health by inhibiting the growth of pathogens, to treat a variety of conditions, including diarrhea in children. Lactobacillus acidophilus -- a tongue-twisting phrase commonly abbreviated as L. acidophilus -- is a common probiotic that exists naturally in some yogurts, as well as in miso and tempeh; it is also sold as a supplement. Although results are mixed, some clinical evidence supports the use of acidophilus in treating intestinal disorders. Consult your child's doctor before giving acidophilus.

Probiotics, including acidophilus, create favorable conditions for beneficial bacteria -- or microflora -- found in the gut, as well as in the vagina and mouth. They do this by forming lactic acid, hydrogen peroxide and antibacterial compounds, which inhibit common pathogens such as E. coli and C. albicans. Probiotics are often prescribed to alleviate diarrhea caused by antibiotics -- which kill beneficial bacteria as well as pathogens -- as well as to promote digestion, alleviate irritable bowel syndrome, improve lactose tolerance, enhance the immune system, and lower the risk of eczema. They are also used for colic in babies, fever blisters, canker sores and hives. In addition to creating intestinal balance, probiotics help break down food and assist in absorption of nutrients. Because acidophilus is acid-resistant, it can persist in the stomach much longer than other bacteria.

Some clinical research supports the use of probiotics for intestinal disorders, but others have shown inconclusive results. In a double-blind randomized study published in March 2001 in "Journal of Pediatrics," researchers found that Lactobacillus G.G. -- a strain related to L. acidophilus -- significantly reduced the risk of rotaviral diarrhea in hospitalized infants. In a review published in February 2009 in "Nutrition in Clinical Practice," the authors examined the role of probiotics in restoring proper balance of microbiota in the gut and reducing levels of diarrhea-causing opportunistic pathogens -- such as C. difficile -- that propagate in the intestine as a result of treatment with broad-spectrum antibiotics. They concluded that probiotics inhibit these pathogens by producing antimicrobial compounds and chemicals, and can help prevent and treat antibiotic-associated diarrhea.

Acidophilus products are labeled by the amount of organisms they contain, with typical doses ranging from 1 to 10 billion organisms. MayoClinic.com advises treating children with a commercial preparation of up to 12 billion heat-killed L. acidophilus every 12 hours for five days. The dosage should be given either 2 hours before or 2 hours after giving antibiotics, which can affect the action of acidophilus. The University of Maryland Medical Center notes that you can treat diaper rash or yeast infections in infants by using a liquid form of acidophilus as a lotion and applying it externally to the diaper area. Ask a doctor before using acidophilus on your child, especially if he is under 3 years old.

Acidophilus -- which is found naturally in the intestinal tract -- is generally considered safe. However, it may be unsafe for children with weakened immune systems or short bowel syndrome. Buy acidophilus from a reputable health foods store; MedlinePlus notes that some products labeled L. acidophilus do not contain any acidophilus bacteria, while others may contain harmful bacteria. You should refrigerate acidophilus. If you are treating your child for diarrhea and symptoms last for more than a day -- or if your child seems dehydrated -- call your doctor.