Acidophilus may be used to reduce susceptibility to vaginal yeast infections, which are quite common. Symptoms including itching, burning, inflammation, and discharge occur due to an overgrowth of the yeast Candida albicans, which is part of the normal vaginal flora. Some women are more prone to yeast infections than others.

Antibiotics destroy the normal probiotic flora, and may lead to yeast infections. High sugar levels are another predisposing factor. Diabetics, who tend to have high blood sugar, and persons who consume a processed diet that is high in sugar have more frequent problems with yeast as well.

The hormonal states created by pregnancy or the use of oral contraceptives also contribute to yeast infections. IUD users can have an increased rate of infection. In rare cases, Candida is sexually transmitted and both partners may require treatment in order to control repeated overgrowth.

Anyone who has AIDS or any other condition causing immunosuppression has increased susceptibility to Candida and other types of infections. Acidophilus is one of the organisms that competes with Candida and decreases its population.

Many studies have shown that oral and topical use (by douching) of acidophilus are effective to prevent and treat this condition. Systemic candidiasis, or yeast hypersensitivity syndrome, is a condition that is not recognized by many allopaths.

It is acknowledged by some practitioners of alternative and complementary medicine as a problem with broad-ranging consequences. This theory holds that some people have an allergic reaction to the yeast and/or its toxins, and that they can experience serious symptoms when the organism multiplies in the body to an abnormal degree.

Fatigue, diarrhea, constipation, muscle pain, thrush, itching, mood changes, endocrine dysfunction, headaches, and tingling or numbness of the extremities are some of the symptoms that are reportedly associated with systemic candidiasis.

A weak immune system may be more prone to allowing yeast to multiply, and large numbers of yeast can act to further suppress the immune function. Acidophilus, in combination with such nutritional supplements as essential fatty acids, is often recommended for the prevention and treatment of this syndrome.

Irritable bowel syndrome (IBS) is a functional disturbance of the lower intestine that can cause bloating, cramping, abdominal pain, diarrhea, constipation, and painful bowel movements. This condition is also known as spastic colon.

One small study of the use of acidophilus to treat IBS showed more improvement in the treated group than in those who took a placebo. This evidence is not conclusive evidence, but in view of the safety of the treatment and the scarcity of effective alternatives, acidophilus may be worth trying.

Traveler’s diarrhea is sometimes suffered by people who consume contaminated food or water in other countries. Some evidence shows that regular use of acidophilus and other probiotics may prevent this condition.

Two clinical studies published in 2007 reported that probiotics, including acidophilus, can be effective in treating IBS and in preventing and treating mild to moderate ulcerative colitis (UC), an inflammation of the walls of the bowel accompanied by the formation of ulcers.

The condition can result in permanent bowel damage. One of the studies also showed probiotics appear to be useful in preventing and treating pouchitis, an acute infection in part of the intestines of patients who have undergone an ileostomy (removal of a pouch at the end of the small intestine) and restorative complete colectomy (removal of all four parts of the colon).

Both studies concluded there is no evidence to suggest probiotics are effective in treating Crohn’s disease, an immune system disorder that effects the small intestine that sometimes spreads to the colon.