Abstract: The present invention provides materials from laver (a seaweed) as the starting material, which are useful in the field of pharmaceutical preparation, the field of health food, etc. The present invention relates to enzyme-decomposed materials from laver comprising a peptide mixture having an antihypertensive action obtained by decomposing laver with pepsin, wherein laver is boiled as a starting material for 1 hour or more and then the broth is removed whereby their antihypertensive action is further raised while their bitter taste, smell, viscosity etc. are eliminated. Accordingly, these enzyme-decomposed materials are made further useful as an antihypertensive agent and also suitable when added to food for use as health food. Further, these materials after decomposed with pepsin are further decomposed with an enzyme having a peptidase activity thereby improving tastes and providing more suitable food additives.