diff --git a/IPython/html/base/handlers.py b/IPython/html/base/handlers.py
index 1e23177..6c3dcdd 100644
--- a/IPython/html/base/handlers.py
+++ b/IPython/html/base/handlers.py
@@ -375,7 +375,8 @@ def json_errors(method):
reply = dict(message=message, reason=None, traceback=tb_text)
self.finish(json.dumps(reply))
else:
- return result
+ # FIXME: can use regular return in generators in py3
+ raise gen.Return(result)
return wrapper