diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
index 5c72df48aa8e..919162b3fd96 100644
--- a/lib/matplotlib/axes/_axes.py
+++ b/lib/matplotlib/axes/_axes.py
@@ -2913,9 +2913,9 @@ def stem(self, *args, linefmt=None, markerfmt=None, basefmt=None, bottom=0,
         basefmt : str, default: 'C3-' ('C2-' in classic mode)
             A format string defining the properties of the baseline.
 
-        orientation : str, default: 'vertical'
+        orientation : {'vertical', 'horizontal'}, default: 'vertical'
             If 'vertical', will produce a plot with stems oriented vertically,
-            otherwise the stems will be oriented horizontally.
+            If 'horizontal', the stems will be oriented horizontally.
 
         bottom : float, default: 0
             The y/x-position of the baseline (depending on orientation).