Keloids are an abnormal response to wound healing distinguished by an overproduction of collagen. Thickened bundles of collagen in the reticular dermis oriented haphazardly in relation to the overlying epithelium are found in keloids, in contrast to thinner collagen fibers in a more orderly arrangement that are found in normal scars. Previous clinical trials of intralesional interferon-gamma (IFN-G) injections by Larrabee et al. and Granstein et al. showed a decrease in lesion size. These findings led to a conclusion that IFN-G would be a useful adjunct to surgical excision of keloids to aid in preventing recurrence. We performed a double-blind, placebo-controlled trial in patients with two or more keloids treated with excision and subsequent local injections of IFN-G or placebo.