diff -r 5bad73fbf593 Doc/library/doctest.rst
--- a/Doc/library/doctest.rst	Sun Apr 29 09:25:25 2012 -0700
+++ b/Doc/library/doctest.rst	Mon Apr 30 15:36:39 2012 +0200
@@ -580,6 +580,10 @@
       Traceback (most recent call last):
       CustomError: message
 
+
+   .. code-block:: python
+      :trim-doctest-flags: disable
+
       >>> raise CustomError('message') #doctest: +IGNORE_EXCEPTION_DETAIL
       Traceback (most recent call last):
       my_module.CustomError: message
diff -r 5bad73fbf593 Doc/tools/sphinxext/pyspecific.py
--- a/Doc/tools/sphinxext/pyspecific.py	Sun Apr 29 09:25:25 2012 -0700
+++ b/Doc/tools/sphinxext/pyspecific.py	Mon Apr 30 15:36:39 2012 +0200
@@ -261,9 +261,46 @@
     return fullname
 
 
+from sphinx.directives import CodeBlock, directives
+from functools import partial
+class ExtendedCodeBlock(CodeBlock):
+    """Code block that can disable the trimming of doctest flag."""
+
+    OPT = 'trim-doctest-flags'
+
+    option_spec = CodeBlock.option_spec.copy()
+    option_spec[OPT] = partial(directives.choice, values=('disable',))
+
+    def run(self):
+        node, = super(ExtendedCodeBlock, self).run()
+        if self.OPT in self.options:
+            node.attributes[self.OPT] = self.options[self.OPT]
+        return [node]
+
+    @classmethod
+    def _patch(cls, original):
+        from functools import wraps
+        @wraps(original)
+        def visit_literal_block(self, node):
+            trimming = node.attributes.get(cls.OPT, '')
+            saved = self.highlighter.trim_doctest_flags
+            if trimming == 'disable':
+                self.highlighter.trim_doctest_flags = False
+            try:
+                original(self, node)
+            finally:
+                self.highlighter.trim_doctest_flags = saved
+        return visit_literal_block
+
+from sphinx.writers.latex import LaTeXTranslator
+LaTeXTranslator.depart_literal_block = ExtendedCodeBlock._patch(LaTeXTranslator.depart_literal_block)
+HTMLTranslator.visit_literal_block = ExtendedCodeBlock._patch(HTMLTranslator.visit_literal_block)
+
+
 def setup(app):
     app.add_role('issue', issue_role)
     app.add_role('source', source_role)
+    app.add_directive('code-block', ExtendedCodeBlock)
     app.add_directive('impl-detail', ImplementationDetail)
     app.add_directive('deprecated-removed', DeprecatedRemoved)
     app.add_builder(PydocTopicsBuilder)