Probiotics works by producing hydrogen peroxide and an organic acid, through spatial exclusion. Spatial exclusion simply means that probiotics crowd out other bacteria, as they compete with bad bacteria for nutrients needed for growth.

If the microflora's balance is disturbed, and dysfunction occurs, probiotics can be used.

Acidophilus treats different kinds of ailments, including:

• Irritable bowel syndrome -- acidophilus relieves bloating, diarrhea, and cramping
• Flatulence -- the gas producers found in large intestines are reduced or prevented from multiplying
• Vaginal yeast -- acidophilus can combat the overgrowth of Candida
• Bad breath
• Urinary tract infections
• Helps in producing immune system cells to fight viral infections
• Improves hypersensitivity among infants with food allergies
• Other health conditions including cancer, cardiovascular disease, constipation, colon cancer, diverticulitis, Crohn's disease, heartburn, indigestion, stomach ulcers, thrush, and ulcerative colitis.

Some people taking acidophilus report allergic reactions such as difficulty in breathing, swelling of lips, face, tongue, throat, or hives. Consult your doctor before taking any dietary supplement.

If you're taking acidophilus, you may be able to feel an increase in gassiness for a few days. This usually happens because the intestines need to adjust with the bacterial shift.