In a 6-month, double-blind, placebo-controlled study, 100 to 150 mg/d indomethacin appeared to protect mild to moderately impaired Alzheimer's disease patients from the degree of cognitive decline exhibited by a well-matched, placebo-treated group. Over a battery of cognitive tests, indomethacin patients improved 1.3% (+/- 1.8%), whereas placebo patients declined 8.4% (+/- 2.3%)--a significant difference (p < 0.003). Caveats include adverse reactions to indomethacin and the limited scale of the trial.