diff --git a/README.md b/README.md
index bf8e591..bf16d0b 100644
--- a/README.md
+++ b/README.md
@@ -30,6 +30,7 @@ options:
 Following additional parameters can be used:
 
  - `-E` / `--skip-errors`
+ - `--use-sphinx-default`
 
 `blacken-docs` will format code in the following block types:
 
@@ -60,6 +61,16 @@ Following additional parameters can be used:
             print("hello world")
 ```
 
+(rst using Sphinx default for blocks marked with `::`)
+``rst
+    hello::
+
+        def hello():
+            print("hello world")
+```
+
+This style is enabled with the `--use-sphinx-default` option.
+
 (rst `pycon`)
 ```rst
     .. code-block:: pycon