For 11 days, an odd-numbered medium-chain triglyceride (trinonanoin, C9TG)/long-chain triglyceride (LCT) emulsion was given parenterally to rabbits, providing 46.5% of total energy. In comparison with LCT or MCT/LCT fat emulsions, no negative effects on organ weights and liver lipid concentrations were noted. In some rabbits of the C9TG/LCT group macroscopically but not histologically visible liver changes were observed. The extent of nonanoic acid deposition in liver triglycerides, liver phospholipids, adipose tissue and skeletal muscle after C9TG/LCT administration was similar to C8/C10 deposition in the MCT/LCT group; the enrichment of adipose tissue with 16 mol% was higher than expected.