The alkamides comprise a group of about 70 biogenetically closely related fatty acid amides with characteristic olefinic and acetylenic patterns. Purely olef inic derivatives have been found, so far, only in the Piperaceae, Aristolochiaceae and Rutaceae, whereas the Asteraceae tribes Heliantheae and Anthemideae additionally contain a great number of different acetylenic amides. With regard to the restricted distribution of alkamides, their occurrence deserves systematic attention and may contribute to a more natural grouping of genera at least within the two latter tribes. Some olefinic isobutylamides have been shown to possess considerable insecticidal activity and to be effective as molluscicides and cercaricides and thus are of potential use against bilharzia. Furthermore, alkamides have been used medicinally since ancient times as sialogogues, antitussives and analgesics. More recently, some acetylenic derivatives have been shown to inhibit the RNA-synthesis in mice-ascites-tumour tests. This review highlights the present state of knowledge on the structural relationships, distribution and biological activities of the alkamides.