Peripheral lymph lipoproteins were studied in four hyperlipidaemic men before and after 6 weeks of treatment with gemfibrozil, a drug which is known to increase the fractional catabolic rate of very low density lipoproteins (VLDL) by raising lipoprotein lipase activity in peripheral tissues. Decreases in plasma triglycerides of 18–60% (mean, 45%) were accompanied by increases in lymph apolipoprotein (apo) A‐I concentration of 30–108% (mean, 66%; P<0.01), and in lymph cholesterol concentration of 35–100% (mean, 59%; P<0.05). The additional lymph cholesterol was distributed over a broad range of lipoprotein particle sizes. Effects on plasma apo A‐I concentration (mean, +7%) and plasma total cholesterol concentration (‐ 7%)) were not statistically significant. No changes were observed in four untreated control subjects. These findings are compatible with the hypothesis that lipolysis of VLDL at the blood‐endothelium interface increases the transfer of apo A‐I from plasma to interstitial fluids, and thereby promotes cholesterol efflux from cells.