A new cyclohexylacetic acid derivative, named 2-{4-hydroxy-7-oxabicyclo [2.2.1] heptanyl}-acetic acid (1), was isolated from Emilia sonchifolia, together with a known analogue, 2-(1,4-dihydroxy cyclohexanyl)-acetic acid (2). Their structures were determined on the basis of spectroscopic techniques including IR, NMR, HR-ESI-MS and X-ray diffraction.