diff --git a/doc/upstream.md b/doc/upstream.md
index efc3045..14e5a5e 100644
--- a/doc/upstream.md
+++ b/doc/upstream.md
@@ -25,5 +25,5 @@ All this params are optional. You should see [Nginx upstream doc](http://nginx.o
 - `backup`
 - `down`
 - `route`
-- `slow`start`
+- `slow_start`