diff --git a/imap_filter/imap_filter.py b/imap_filter/imap_filter.py
index 4a2a5cf..40abacd 100644
--- a/imap_filter/imap_filter.py
+++ b/imap_filter/imap_filter.py
@@ -211,6 +211,10 @@ class ImapFilter:
             part = str(data[1])
         message = email.message_from_string(part)
         decoded_field = email.header.decode_header(message.get(mfilter['field'], ""))
+        self._log.debug(
+            "Decoded field: %s",
+            decoded_field
+        )
         if isinstance(decoded_field[0][0], str):
             field_data = decoded_field[0][0]
         else: