The author applies the theory of public goods on donated blood. Donated blood may be taken as a 'public good' like water and air, police and fire brigades. This theory trends to imply a preference for voluntary donation and bloodbanking by public and nonprofit organisations as well as for low cost supply. An additional commercial supply of blood nevertheless is welcome. Quality as well as quantity of blood depend first of all on the willingness to donate and the honesty of the donors about their health. An altruistic motivation alone, which is not triggered by some material incentive, does not in all systems guarantee a sufficient quantity of safe blood. Both the altruistic as well as the reimbursement-oriented donor's willingness and honesty have to be guarded by sound practice in bloodbanking and adequate public control within a legal framework which reflects the vital role of blood supply. A legal implementation of product liability will certainly be an important instrument in this field.