Postmortem diagnostics of anaphylactic and anaphylactoid reaction as the cause of death in cases of sudden deaths without witnesses, as well as those in which circumstances of sudden disease and then death are known, seems to be very difficult. This is caused by the lack of characteristic macro- or microscopic changes to internal organs resulting from a short, or even very short time, that elapses from the action of the etiological factor till death. In the above mentioned cases it is often impossible to establish univocally the cause of death, despite considering information on the cause of disease and its clinical symptoms. On the basis of 2 cases of sudden deaths resulted from the intake of hazel nuts, and the administration of contrast agent before radiological examination, the authors discuss the usefulness of postmortem determinations of tryptase and IgE in blood for diagnostics of deaths resulting from anaphylactic and anaphylactoid reaction, respectively.