Gambierol is a polycyclic ether toxin with the same biogenetic origin as ciguatoxins. Gambierol has been associated with neurological symptoms in humans even though its mechanism of action has not been fully characterized. We studied the effect of gambierol in human neuroblastoma cells by using bis-oxonol to measure membrane potential and FURA-2 to monitor intracellular calcium. We found that this toxin: i) produced a membrane depolarization, ii) potentiated the effect of veratridine on membrane potential iii) decreased ciguatoxin-induced depolarization and iv) increased cytosolic calcium in neuroblastoma cells. These results indicate that gambierol modulate ion fluxes by acting as a partial agonist of sodium channels.