Dactylamides A (1) and B (2), two new tryptophan-derived dipeptides were isolated from the sea hare Aplysia dactylomela and structurally characterised by spectroscopic methods and synthesis of deoxy-analogues. Isolaurenisol, allolaurinterol, their respective acetates and aplysioviolin, isolated as the bioactive constituents of the sea hare, were also structurally characterised and evaluated in a range of biological assays.