diff --git a/pandas/util/__init__.py b/pandas/util/__init__.py
index a462080f328f4..4d5ef69a7ecfa 100644
--- a/pandas/util/__init__.py
+++ b/pandas/util/__init__.py
@@ -9,14 +9,29 @@ def __getattr__(key: str):
 
         return hash_pandas_object
     if key == "Appender":
+        import warnings
+
+        from pandas.errors import Pandas4Warning
         from pandas.util._decorators import Appender
 
+        warnings.warn(
+            "Appender is deprecated and will be removed in a future version.",
+            Pandas4Warning,
+            stacklevel=2,
+        )
         return Appender
     if key == "Substitution":
+        import warnings
+
+        from pandas.errors import Pandas4Warning
         from pandas.util._decorators import Substitution
 
+        warnings.warn(
+            "Substitution is deprecated and will be removed in a future version.",
+            Pandas4Warning,
+            stacklevel=2,
+        )
         return Substitution
-
     if key == "cache_readonly":
         from pandas.util._decorators import cache_readonly