Abstract Etna volcano is characterized by frequent effusive eruptions from the summit craters or from flank fissures, and these have often threatened villages, infrastructures and tourist facilities. Considerable experience of lava-flow mitigation has been gained by scientists working on this volcano, and in this paper we principally discuss the problems arising from lava flows emplaced during the 2002–03 flank eruption, when eruptive fissures opened both on the northern and southern flanks of the volcano, feeding lava flows towards several villages, tourist facilities and forests. We highlight the importance of the monitoring system to follow the spreading of eruptive fissures and predict when they stopped propagating. We illustrate the value of thermal mapping in identifying active lava flows, in measuring effusion rates to estimate the maximum distance that flows can travel, and in obtaining reliable lava-flow simulations in real time in order to predict possible paths of the lava flow and to adopt the most appropriate solutions to limit its damage. Collaborations between scientists from different institutions and fields once again proved essential to understand and model the eruptive processes, to mitigate hazards and to obtain the best results.