Methods for lowering serum triglycerides use pharmaceutical agents and food products that have no side effects, are easy to ingest continuously, and have a serum triglyceride-lowering effect are provided. The pharmaceutical agents and food products are lipid metabolism-ameliorating agents and serum triglyceride-lowering agents, which include as an active ingredient a culture of a bacterium belonging to the genus Bacillus. The bacterium belongs to the genus Bacillus is preferably Bacillus subtilis, and more preferably Bacillus subtilis C-3102 (FERM BP-1096). The lipid metabolism-ameliorating agent and the serum triglyceride-lowering agent are useful for treating and preventing diseases such as arteriosclerosis.
