Aldehyde dehydrogenases (ALDHs) detoxify toxic aldehydes by oxidation to the corresponding carboxylic acids. Long-chain aliphatic aldehydes are largely produced by catabolic metabolism of several lipids, including ether glycerolipids, fatty alcohols, sphingolipids and wax esters. Some medium-chain aliphatic aldehydes, such as hexanal, octanal and 4-hydroxy-2-nonenal (4HNE) are produced via lipid peroxidation during oxidative stress. Aldehyde dehydrogenase family 3 member B1 (ALDH3B1) is able to oxidise both medium- and long-chain aldehydes. C16 aldehydes such as hexadecanal (HXAL) generated through sphingolipid metabolism on the plasma membrane can be oxidised to palmitic acid (PALM) (Kitamura et al. 2013). 4HNE, amongst other reactive medium-chain aldehydes, can be detoxified by oxidation to 4-hydroxynonenoic acid (4HNA) by ALDH3B1, suggesting a potential physiological role for ALDH3B1 against oxidative stress (not shown here) (Marchitti et al. 2010).