The milk cap's fruit bodies have a characteristic orange milk juice (latex). The guaiane sesquiterpenes are responsible for the orange colour. Sesquiterpenes are terpenes composed of three isoprene units and therefore have 15 carbon atoms. Sesquiterpenes are widely distributed in nature and are found in plants as well as animals, for example in the juvenile hormone of insects. Plants use sesquiterpenes as a defense compound against insects. According to some studies, sesquiterpenes have antibiotic, anticarcinogenic, or immunostimulant effects. Young, uninjured fruit bodies of "L. deterrimus" have sesquiterpenoides in the form of fatty acid dihydroazulene-esters. About 85% of the yellow-coloured dihydroazulene are esterified with stearic acid and about 15% with linoleic acid. If the fruit body is injured, the free sesquiterpene – a dihydroazulene alcohol – is released enzymatically. Several products are produced from it through oxidation: the yellow-coloured aldehyde delicial (1-formyl-6, 7-dihydro-4-methyl-7-isopropenylazulene), the purple-coloured aldehyde lactarovioline (1-formyl-4-methyl-7-isopropenylazulene), and the blue-coloured alcohol deterrol (1-hydroxymethyl-4-methyl-7-isopropenylazulene). The milk is first maroon through mixing with the different colours and discolours green. The dihydroazulene alcohol and delicial are unstable compounds, which react to form further products. Delicial polymerises particularly slight.