Abstract Seedlings obtained from seeds of three populations of oregano (Origanum ehrenbergii) harvested in Lebanon and sown at a research station in France were planted in three replicates in a Fischer block design. Oils produced by water distillation were subjected to analysis by GC and GC/MS. The oils of one of the populations were uniform and carvacrol-rich. The other population displayed a variable chemical composition, including thymol, thymol-carvacrol and p-cymene/Î³-terpinene chemotypes.