The effects of docosahexaenoyl dopamine and docosahexaenoic acid on the regeneration of hydra gastric and basal fragments are studied. Docosahexaenoyl dopamine induced morphogenetic abnormalities such as single ectopic tentacles in the gastric region and projections in the gastric and basal regions. Docosahexaenoic acid had no effect on the morphogenesis except for a mild slowing of the regeneration rate. Since no hydrolysis of docosahexaenoyl dopamine was detected in hydra extract, it was assumed that the morphogenetic effect could be associated with the dopamine component of this complex. © 2010 Pleiades Publishing, Ltd.