The ocular irritancy potential of surfactants of the anionic and non-ionic type, derived from lysine has been tested by the hen's egg test-choriollantoic membrane (HET-CAM) to correlate the potential irritation with the structure of the surfactant, in order to synthesize the less irritant surfactant for their use in the pharmaceutical and cosmetics industry. The anionic compounds, independently of the counterion, showed an irritant action higher than non-ionic surfactants. Among the anionic surfactants the presence of lysine as cation reduced the degree of irritation; nevertheless, the salt of lysine of lauric acid was a severe irritant. The non-ionic surfactant with two chains was less irritant than the corresponding compound with one chain and represented the best compound for ocular application. The time of appearance of haemorrhage, vasoconstriction and coagulation is used to evaluate the degree of irritation. There was a close relationship between the concentration and the time of the appearance of vasoconstriction at the concentrations tested.