Mildew is a destructive growth that feeds on a variety of organic materials such as cotton, wood and leather. While dormant mildew exists freely in the environment, conditions of dampness and warmth can provide the ingredients for rapid growth, frequently within 72 hours.  Some individuals are sensitive to mildew and experience an allergic reaction in its presence.

Since mildew feeds on organic materials, it eventually causes a loss in fiber strength and unsightly staining or discoloration. These effects are not reversible. Once deteriorated by mildew, textile fibers are permanently affected. The gray splotches that sometimes develop on walls and fibers following water damage are colonies of the mildew fungi and represent an advanced stage of growth.

The characteristic musty odor of mildew results from its digestive action. The odor disappears when the mildew has been eliminated and the absence of odor is evidence that improvement has occurred.

A variety of fungicidal solutions are available that kill mildew without damaging fabrics. They must come in direct contact with the organism to be effective, and the procedures sometimes require multiple treatments. Because many household items utilize organic materials, these furnishings are frequently affected by mildew, especially in humid environments. Oriental rugs, upholstery fabrics and clothing in closets are frequent victims. Thorough drying is an essential step in mildew removal.

Complete and permanent elimination of mildew requires that the conditions that stimulate mildew growth—primarily dampness—be eliminated. No matter what germicides are employed, a continuing damp condition at temperatures over 65°F (l8°C) will eventually result in renewed mildew growth.