diff --git a/actionpack/lib/action_dispatch/http/response.rb b/actionpack/lib/action_dispatch/http/response.rb
index 91cf4784db..8760319001 100644
--- a/actionpack/lib/action_dispatch/http/response.rb
+++ b/actionpack/lib/action_dispatch/http/response.rb
@@ -172,6 +172,7 @@ module ActionDispatch # :nodoc:
       stream.to_path
     end
 
+    # Returns the content of the response as a String.
     def body
       strings = []
       each { |part| strings << part.to_s }