diff --git a/synapse/api/errors.py b/synapse/api/errors.py
index 23ce0af27..ad79bc7ff 100644
--- a/synapse/api/errors.py
+++ b/synapse/api/errors.py
@@ -39,6 +39,7 @@ class CodeMessageException(Exception):
         super(CodeMessageException, self).__init__("%d: %s" % (code, msg))
         self.code = code
         self.msg = msg
+        self.response_code_message = None
 
     def error_dict(self):
         return cs_error(self.msg)
@@ -107,6 +108,7 @@ class LimitExceededError(SynapseError):
                  errcode=Codes.LIMIT_EXCEEDED):
         super(LimitExceededError, self).__init__(code, msg, errcode)
         self.retry_after_ms = retry_after_ms
+        self.response_code_message = "Too Many Requests"
 
     def error_dict(self):
         return cs_error(
diff --git a/synapse/handlers/_base.py b/synapse/handlers/_base.py
index 935adea1a..57429ad2e 100644
--- a/synapse/handlers/_base.py
+++ b/synapse/handlers/_base.py
@@ -39,7 +39,7 @@ class BaseHandler(object):
         )
         if not allowed:
             raise LimitExceededError(
-                retry_after_ms=1000*(time_allowed - time_now),
+                retry_after_ms=int(1000*(time_allowed - time_now)),
             )
 
 
diff --git a/synapse/http/server.py b/synapse/http/server.py
index 0b87718bf..74c220e86 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -140,7 +140,8 @@ class JsonResource(HttpServer, resource.Resource):
             self._send_response(
                 request,
                 e.code,
-                cs_exception(e)
+                cs_exception(e),
+                response_code_message=e.response_code_message
             )
         except Exception as e:
             logger.exception(e)
@@ -150,7 +151,8 @@ class JsonResource(HttpServer, resource.Resource):
                 {"error": "Internal server error"}
             )
 
-    def _send_response(self, request, code, response_json_object):
+    def _send_response(self, request, code, response_json_object,
+                       response_code_message=None):
         # could alternatively use request.notifyFinish() and flip a flag when
         # the Deferred fires, but since the flag is RIGHT THERE it seems like
         # a waste.
@@ -166,7 +168,8 @@ class JsonResource(HttpServer, resource.Resource):
             json_bytes = encode_pretty_printed_json(response_json_object)
 
         # TODO: Only enable CORS for the requests that need it.
-        respond_with_json_bytes(request, code, json_bytes, send_cors=True)
+        respond_with_json_bytes(request, code, json_bytes, send_cors=True,
+                                response_code_message=response_code_message)
 
     @staticmethod
     def _request_user_agent_is_curl(request):
@@ -350,7 +353,8 @@ class ContentRepoResource(resource.Resource):
                 send_cors=True)
 
 
-def respond_with_json_bytes(request, code, json_bytes, send_cors=False):
+def respond_with_json_bytes(request, code, json_bytes, send_cors=False,
+                            response_code_message=None):
     """Sends encoded JSON in response to the given request.
 
     Args:
@@ -362,7 +366,7 @@ def respond_with_json_bytes(request, code, json_bytes, send_cors=False):
     Returns:
         twisted.web.server.NOT_DONE_YET"""
 
-    request.setResponseCode(code)
+    request.setResponseCode(code, message=response_code_message)
     request.setHeader(b"Content-Type", b"application/json")
 
     if send_cors: