diff --git a/lib/wechat/message.rb b/lib/wechat/message.rb
index <HASH>..<HASH> 100644
--- a/lib/wechat/message.rb
+++ b/lib/wechat/message.rb
@@ -69,8 +69,8 @@ module Wechat
       end
     end
 
-    def to(userid)
-      update(ToUserName: userid)
+    def to(openid_or_userid)
+      update(ToUserName: openid_or_userid)
     end
 
     def agent_id(agentid)
Still possible openid as 'to' is shared between public account and enterprise account.