diff --git a/.vimrc b/.vimrc
index 7f8fa33..15e0025 100644
--- a/.vimrc
+++ b/.vimrc
@@ -311,7 +311,7 @@ imap <S-F1> <Esc><S-F1>
 " show contextual help with F1
 function Help()
         try
-        if b:current_syntax == "python"
+        if exists('b:current_syntax') && b:current_syntax == "python"
                 :call ShowPyDoc(expand("<cword>"), 1)
         else
                 execute "Man " . expand("<cword>")