The oils isolated from the aerial parts of Ridolfia segetum (L.) Moris (Apiaceae) gathered in Castilla la Mancha (Spain) were analyzed by capillary GC and GC/MS. The oil from the flowers was dominated by α-phellandrene (32.0â33.8%), terpinolene (18.0â21.4%) and (Z)-β-ocimene (12.4â14.5%), while the main components of the fruit oils were found to be dillapiole (5.1â39.6%), β-pinene (10.3â20.9%), α-pinene (3.0â16.1%), α-phellandrene (13.7â15.3%) and (Z)-β-ocimene (8.1â12.8%). The oil from the stems was characterized by a high content of p-cymene (15.1â79.5%), (Z)-β-ocimene(0.9â38.5%) and α-phellandrene (1.1â14.4%), whereas the oil from the leaves was shown to contain p-cymene (8.8â83.6%), (Z)-β-ocimene (t-32.6%), myrcene (t-12.5%) and β-pinene (2.1â12.1%) as major constituents. © 2005, Taylor &amp; Francis Group, LLC. All rights reserved.