A placebo-controlled trial of a proprietary extract of North American ginseng (CVT-E002) to prevent acute respiratory illness in institutionalized older adults.

Objectives: To compare a proprietary extract of American ginseng, CVT-E002, with placebo in preventing acute respiratory illness (ARI) in an institutional setting during the influenza season.

Design: Two randomized, double-blind, placebo-controlled trials conducted late in the 2000 (8 week) and 2000-2001 (12 week) influenza seasons.

Setting: Long-term care setting that included nursing home and assisted living at three sites.