diff --git a/src/corelib/text/qstring.cpp b/src/corelib/text/qstring.cpp
index ad0d062e348..fd276e1ac6a 100644
--- a/src/corelib/text/qstring.cpp
+++ b/src/corelib/text/qstring.cpp
@@ -3786,6 +3786,9 @@ static void replace_helper(QString &str, QSpan<size_t> indices, qsizetype blen,
   but \a position + \a n goes outside the strings range,
   then \a n will be adjusted to stop at the end of the string.
 
+  \note If you use an empty \a before argument, the \a after argument will be
+  inserted \e {before and after} each character of the string.
+
   Example:
 
   \snippet qstring/main.cpp 40
diff --git a/src/corelib/text/qstringlist.cpp b/src/corelib/text/qstringlist.cpp
index 61923e0b3f2..2cc5d0c7f72 100644
--- a/src/corelib/text/qstringlist.cpp
+++ b/src/corelib/text/qstringlist.cpp
@@ -382,6 +382,9 @@ QStringList QtPrivate::QStringList_filter(const QStringList *that, const QRegula
     text replaced with the \a after text wherever the \a before text
     is found.
 
+    \note If you use an empty \a before argument, the \a after argument will be
+    inserted \e {before and after} each character of the string.
+
     \include qstringlist.cpp comparison-case-sensitivity
 
     For example: