Four phenylpropanoids, forsythoside B 1, lysionotoside 2, verbascoside 3, betonyoside F 4, an iridoid, verminoside 5, seven flavonoids, compounds 6-12, and two betaine derivatives 13 and 14 were isolated from the aerial parts of Ballota undulata. The structures of the isolated compounds were established by high resolution NMR and ESI-MS. The antioxidant activity of all compounds was determined by measuring free radical scavenging activity by TEAC test. (c) 2004 Elsevier Ltd. All rights reserved.