['The efflux of cellular cholesterol mediated by apolipoprotein (apo)A-I and ATP-binding cassette transporter A1 (ABCA1) is a major pathway of reverse cholesterol transport. We investigated the effect of aspirin on this process.', 'The expression levels of ABCA1 in RAW264.7 cells were determined using reverse transcription polymerase chain reaction and Western blot analysis. ³H-cholesterol efflux was measured by scintillation counting.', '0.5 mmol/l aspirin increased apoA-I-mediated cholesterol efflux and increased the expression of ABCA1. By increasing the dose of aspirin higher than 0.5 mmol/l, ABCA1 expression and function were significantly decreased. In cells transfected with a specific peroxisome proliferator-activated receptor (PPAR)-α small interfering RNA, the induction of ABCA1 expression and apoA-I-mediated ³H-cholesterol efflux by aspirin were substantially suppressed.'] Does aspirin increase apolipoprotein-A-I-mediated cholesterol efflux via enhancing expression of ATP-binding cassette transporter A1?