diff --git a/skimage/morphology/grey.py b/skimage/morphology/grey.py
index 19a4a346..cd3dcaa8 100644
--- a/skimage/morphology/grey.py
+++ b/skimage/morphology/grey.py
@@ -8,6 +8,7 @@ from . import cmorph
 __all__ = ['erosion', 'dilation', 'opening', 'closing', 'white_tophat',
            'black_tophat']
 
+
 @default_fallback
 def erosion(image, selem=None, out=None, shift_x=False, shift_y=False):
     """Return greyscale morphological erosion of an image.
@@ -35,6 +36,12 @@ def erosion(image, selem=None, out=None, shift_x=False, shift_y=False):
     eroded : uint8 array
         The result of the morphological erosion.
 
+    Notes
+    -----
+    For `uint8` (and `uint16` up to a certain bit-depth) data, the lower
+    algorithm complexity makes the `skimage.filter.rank.minimum` function more
+    efficient for larger images and structuring elements.
+
     Examples
     --------
     >>> # Erosion shrinks bright regions
@@ -90,6 +97,12 @@ def dilation(image, selem=None, out=None, shift_x=False, shift_y=False):
     dilated : uint8 array
         The result of the morphological dilation.
 
+    Notes
+    -----
+    For `uint8` (and `uint16` up to a certain bit-depth) data, the lower
+    algorithm complexity makes the `skimage.filter.rank.maximum` function more
+    efficient for larger images and structuring elements.
+
     Examples
     --------
     >>> # Dilation enlarges bright regions