diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index ee48f546815bb..1a0d564197417 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -531,6 +531,7 @@ class DataFrame(NDFrame, OpsMixin):
         will perform column selection instead.
     dtype : dtype, default None
         Data type to force. Only a single dtype is allowed. If None, infer.
+        If ``data`` is DataFrame then is ignored.
     copy : bool or None, default None
         Copy data from inputs.
         For dict data, the default of None behaves like ``copy=True``.  For DataFrame
diff --git a/pandas/core/series.py b/pandas/core/series.py
index 9209a80ada0d1..f340821775015 100644
--- a/pandas/core/series.py
+++ b/pandas/core/series.py
@@ -256,6 +256,7 @@ class Series(base.IndexOpsMixin, NDFrame):  # type: ignore[misc]
         Data type for the output Series. If not specified, this will be
         inferred from `data`.
         See the :ref:`user guide <basics.dtypes>` for more usages.
+        If ``data`` is Series then is ignored.
     name : Hashable, default None
         The name to give to the Series.
     copy : bool, default False