diff --git a/doc/en/assert.txt b/doc/en/assert.txt
index 6411ed596..247522c45 100644
--- a/doc/en/assert.txt
+++ b/doc/en/assert.txt
@@ -78,6 +78,12 @@ and if you need to have access to the actual exception info you may use::
 
     # do checks related to excinfo.type, excinfo.value, excinfo.traceback
 
+``excinfo`` is a `py.code.ExceptionInfo`_ instance, which is a wrapper around
+the actual exception raised.
+
+.. _py.code.ExceptionInfo:
+    http://pylib.readthedocs.org/en/latest/code.html#py-code-exceptioninfo
+
 If you want to write test code that works on Python 2.4 as well,
 you may also use two other ways to test for an expected exception::