diff --git a/ftl/core/fields.ftl b/ftl/core/fields.ftl
index 1f3bd6a5e..1e2a002b4 100644
--- a/ftl/core/fields.ftl
+++ b/ftl/core/fields.ftl
@@ -12,4 +12,5 @@ fields-reverse-text-direction-rtl = Reverse text direction (RTL)
 fields-size = Size:
 fields-sort-by-this-field-in-the = Sort by this field in the browser
 fields-that-field-name-is-already-used = That field name is already used.
-fields-name-first-letter-not-valid = The field name should not start with #, ^ or /.
\ No newline at end of file
+fields-name-first-letter-not-valid = The field name should not start with #, ^ or /.
+fields-name-invalid-letter = The field name should not contain :, ", { or }.
diff --git a/qt/aqt/fields.py b/qt/aqt/fields.py
index 06f40b9a5..2cd977c3d 100644
--- a/qt/aqt/fields.py
+++ b/qt/aqt/fields.py
@@ -88,6 +88,10 @@ class FieldDialog(QDialog):
         if txt[0] in "#^/":
             showWarning(tr(TR.FIELDS_NAME_FIRST_LETTER_NOT_VALID))
             return
+        for letter in """:{"}""":
+            if letter in txt:
+                showWarning(tr(TR.FIELDS_NAME_INVALID_LETTER))
+                return
         for f in self.model["flds"]:
             if ignoreOrd is not None and f["ord"] == ignoreOrd:
                 continue