AbstractRacemic helenynolic acid has been prepared from crepenynic acid by epoxidation followed by base‐catalyzed rearrangement. This may be the pathway by which helenynolic acid is produced inHelichrysum bracteatum seed oil from the crepenynic acid also present. A reinvestigation of the epoxy acids in this oil has shown thatcis‐9,10‐epoxyoctadec‐12‐ynoic acid accompanies the coronaric acid previously identified.