The influence of Pieris brassicae feeding on kale was monitored, by evaluating its effect in the volatiles released by the plant through time. This is the first study applying headspace solid-phase microextraction (HS-SPME) and GC/IT-MS to an isolated insect, as most studies analyse the insect-plant system as a whole, being unable to evaluate the contribution of the insect itself. Several HS-SPME assay conditions were tried to maintain the insect alive, mimicking what happens in nature. Substantial differences were noticed between the volatiles composition of kale before and after insect’s attack. More than 60 compounds were found, including terpenes, lipoxigenase pathway by-products, ketones, norisoprenoids, among others. After insect’s attack, l-camphor, sabinene and α-thujene were found and limonene and eucalyptol suffered a noticeable increase. A considerable raise in (Z)-3-hexenyl acetate was observed. In vivo accumulation of limonene and camphor by the insect was detected. The findings contribute to the knowledge of the ecological interactions between the two species.