This study of lipids of Lactarius uvidus has revealed the presence of new fatty acid esters of uvidin A [2a-d] and drimenol [6a-d]. Treatment of uvidin A [1] with base induced a Favorskii-like rearrangement leading to compounds with a new sesquiterpenoid skeleton. Uvidin A [1] showed insect antifeedant and cytotoxic activities.