Investigation and evaluation of antifibrinolytic activity of some new compounds has been carried out using two technics based, one on the "standard clots" method and the other one on labelled clots methods. 2) Among the first four members of the linear amino diacids 2-aminopimelic acid possesses a slight antifibrinolytic activity, the others are non active. 3) The two dipeptides having the same chain length as EACA behave differently ; beta alanyl-glycine is practically inactive whilst glycyl-beta alanine possesses a significant inhibiting power. The question is raised as to whether this active dipeptide might play an antifibrinolytic role in the organism. 4) Among the cyclic epsilon-amino acids tested, alpha aminocampholic acid and dl cis (2,2 dimethyl-3-alpha-aminoethyl) cyclobutaneacetic acid possess and activity slightly superior to that of EACA.
