Serum and lipoprotein lipid levels, oral glucose tolerance and side‐effects were compared in an open cross‐over study of 31 non‐diabetic patients with hypertriglyceridaemia (type II B and IV) before and after 6 weeks of treatment with nicotinic acid (3 g daily) and acipimox (0.75 g daily), a new nicotinic acid‐like drug, respectively. Acipimox was about equally potent in reducing serum and VLDL lipid levels and in increasing HDL cholesterol levels. Acipimox had no significant negative effects on glucose metabolism measured by an oral glucose tolerance test compared with nicotinic acid, which decreased the late glucose tolerance as well as the area under the glucose curve (P < 0.05 for the difference between the two treatments). The incidence and severity of flush or any other recorded side‐effects was higher after nicotinic acid treatment than after acipimox. In addition, no effects on laboratory parameters such as liver enzymes and uric acid were seen after treatment with acipimox. The results of this study demonstrate that acipimox is a satisfactory alternative to nicotinic acid in patients with hypertriglyceridaemia.