Variations in the essential oil composition of aerial parts of pineapple weed (Chamomilla suaveolens (Pursh) Rydb.) growing wild in Estonia, were determined using GC/FID and GC/MS. Forty-four components were identified, representing over 90% of the total oil. Nine compounds have not been mentioned in the literature before. The principal biologically active compounds in C. suaveolens oils were (Z)-en-yne-dicycloether (17.0-40.7%), (E)-beta-farnesene (19.5-32.2%), geranyl isovaleriate (8.4-18.4%), palmitic acid (0.3-9.4%) and myrcene (1.1-7.9%). The investigation seems to approve the benefit of using aerial parts of pineapple weed as the substitute for flowers.