Normal Flora Definition

The bacteria, fungi, and other microorganisms naturally present within the environment of the healthy body. Normal flora exist on the surface of the skin, within natural cavities such as the nose and mouth, in the gastrointestinal tract, and in the reproductive tract.

These beneficial microbes participate in the body’s immune response, digestive functions, and reproductive functions, among others.

Normal flora microbes exist in a balance that prevents one type of microbe from overpowering another. Circumstances that change this balance may allow illness to develop. Antibiotic therapy targets bacteria, for example, though antibiotics cannot distinguish between normal flora and pathogenic bacteria.

So antibiotic medications, particularly broad-spectrum antibiotics, kill bacteria in the gastrointestinal tract and the reproductive tract at the same time they kill pathogenic bacteria. The result may be diarrhea or yeast vaginitis.

See also FUNGUS; INFECTION.

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