A reliable supercritical fluid chromatography (SFC) method was developed for the analysis of lovastatin, a hypocholesterolaemic drug, from MEVACOR®. Methanol-modified carbon dioxide was shown to elute the drug, and its dehydrolovastatin and hydroxy acid lovastatin degradation products from a Hypersil® silica column. However, the hydroxy acid lovastatin was found to tail in this mobile phase. The phenomena was eliminated by the addition of trifluoroacetic acid [Haouck, S. Thomas, D. K. Ellison, Talanta 40 (1993) 491] to the mobile phase which permitted the drug and its two main degradation products to all elute from the Hypersil® silica column in under 6 min with symmetrical peak shape. Chromatographic limit of detection (LOD) and limit of quantification (LOQ), linear dynamic range (LDR), and injection precision were obtained in order to assess the chromatographic performance of the SFC system for the lovastatin separation.