Employers are beginning to realize that they face a nearly invisible but significant drain on productivity: presenteeism, the problem of workers being on the job but, because of illness or other medical conditions, not fully functioning. By some estimates, the phenomenon costs U.S. companies more than $150 billion a year--much more than absenteeism does. Yet, it's harder to identify. As companies struggle to rein in health care costs, most overlook what may be a $150 billion problem: the nearly invisible drain on worker productivity caused by such common ailments as hay fever, headaches, and even heartburn. However, a handful of companies are recognizing the problem of presenteeism and trying to do something about it.

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