Lysophosphatidylcholine, a product of phospholipase A2-mediated hydrolysis of phosphatidylcholine, exhibits membranolytic activity. Therefore, its intracellular levels are under rigid control in normal cells, but accumulate in tissues under stress, e.g., ischemic myocardium. O-Stearoylethanolamine, a structural isomer of N-stearoylethanolamine, a single-chain lipid with putative stress fighting ability, forms bilayer structure at 1 : 1 (mol/mol) mixture with lysophosphatidylcholine. This suggests that O-stearoylethanolamine can buffer the membranolytic effect of lysophosphatidylcholine, which may play a role in the stress-combating responses of organisms.