It has been stated that mythical delusion can block schizophrenic symptoms. However, there are some schizophrenics in whom mythical delusion does not react against schizophrenic symptoms. Three cases are reported of mythical delusion and what conditions are necessary for the mythical delusion to "block" schizophrenic symptoms are considered. Such "blocking' can be found in the mythical delusion which mediates between schizophrenic symptoms and reality. Conversely, when there is no relationship between mythical delusion and schizophrenic symptoms "blocking' cannot be expected.