A double-blind, placebo-controlled trial was conducted to determine the effects of the nonsteroidal anti-inflammatory drug Naprosyn (naproxen) on gingival inflammation. The enrollment of 114 patients provided 102 patients valid for efficacy evaluation, each having a mean gingival index (GI) score of 1.5 or greater at test-teeth sites. Patients were given oral Naprosyn 500 mg b.i.d. or placebo for 30 days. At 28 d, full-mouth prophylaxis was performed. Gingival index, modified sulcular bleeding index (SBI), and plaque index (PII) scores were taken at baseline, at 28 d, and at 30 d. When the 28-d index measurements were compared to baseline, the drug had no significant effect on plaque index scores or gingival inflammation. Statistically, Naprosyn enhanced the resolution of gingival inflammation following removal of microbial plaque. Thus, although this drug does not suppress the inflammation-inducing properties of plaque, Naprosyn may enhance recovery following plaque removal.