Studies on the venom of species inducing Irukandji syndrome are summarized in the recent review on jellyfish causing this syndrome (Gershwin et al., 2013). Pharmacological studies were performed on unfractionated venom from Carukia Barnesi, Alatina Mordens, Malo Kingi, and Malo Maxima to understand the cardiac dysfunction described in the syndrome. The in vitro effect of the venom from Carukia Barnesi was described in a more recent publication (Pereira and Seymour, 2013). The cell metabolism of human cardiomyocytes and skeletal cells was similar to the control without venom, at all the doses tested. This result is consistent with a hypothesis that the cardiac effect associated with the syndrome is an indirect effect of the toxin. SDS-PAGE profiles were published, with bands between 10 and 200 kDa, but no protein was purified (Gershwin et al., 2013).