<jats:p>Crotalaria crispata F. Muell. ex Benth. contains monocrotaline and two isomeric alkaloids of empirical formula C16H23O5N. One of these is identical with fulvine, an alkaloid from Crotalaria fulva Roxb., while the other is new and is named crispatine. Fulvine and crispatine are shown to be macrocyclic esters of retronecine with different diastereoisomers of 3-hydroxy-2,3,4-trimethylglutaric acid.