diff --git a/w3lib/html.py b/w3lib/html.py
index 9990a35..55fe5e3 100644
--- a/w3lib/html.py
+++ b/w3lib/html.py
@@ -220,7 +220,7 @@ def remove_tags_with_content(text, which_ones=(), encoding=None):
 
     text = to_unicode(text, encoding)
     if which_ones:
-        tags = '|'.join([r'<%s.*?</%s>|<%s\s*/>' % (tag, tag, tag) for tag in which_ones])
+        tags = '|'.join([r'<%s\b.*?</%s>|<%s\s*/>' % (tag, tag, tag) for tag in which_ones])
         retags = re.compile(tags, re.DOTALL | re.IGNORECASE)
         text = retags.sub(u'', text)
     return text

diff --git a/tests/test_html.py b/tests/test_html.py
index 68133cb..6d6e8ae 100644
--- a/tests/test_html.py
+++ b/tests/test_html.py
@@ -184,6 +184,10 @@ class RemoveTagsWithContentTest(unittest.TestCase):
         # text with empty tags
         self.assertEqual(remove_tags_with_content(u'<br/>a<br />', which_ones=('br',)), u'a')
 
+    def test_tags_with_shared_prefix(self):
+        # https://github.com/scrapy/w3lib/issues/114
+        self.assertEqual(remove_tags_with_content(u'<span></span><s></s>', which_ones=('s',)), u'<span></span>')
+
 
 class ReplaceEscapeCharsTest(unittest.TestCase):
     def test_returns_unicode(self):

remove_tags_with_content bug
use this 
`remove_tags_with_content("""<div class="hqimg_related"><div class="to_page"><span>热点栏目</span> <s class='hotSe'></s>""", ("s",))`
get result:
`<div class="hqimg_related"><div class="to_page">`
There may be some mistakes
then modified the expression. 
`tags = '|'.join([r'<%s\s+.*?</%s>|<%s\s*/>' % (tag, tag, tag) for tag in which_ones])`
finally,it's work fine

tests/test_html.py::RemoveTagsWithContentTest::test_tags_with_shared_prefix
tests/test_html.py::RemoveEntitiesTest::test_browser_hack tests/test_html.py::RemoveEntitiesTest::test_encoding tests/test_html.py::RemoveEntitiesTest::test_illegal_entities tests/test_html.py::RemoveEntitiesTest::test_keep_entities tests/test_html.py::RemoveEntitiesTest::test_missing_semicolon tests/test_html.py::RemoveEntitiesTest::test_regular tests/test_html.py::RemoveEntitiesTest::test_returns_unicode tests/test_html.py::ReplaceTagsTest::test_replace_tags tests/test_html.py::ReplaceTagsTest::test_replace_tags_multiline tests/test_html.py::ReplaceTagsTest::test_returns_unicode tests/test_html.py::RemoveCommentsTest::test_no_comments tests/test_html.py::RemoveCommentsTest::test_remove_comments tests/test_html.py::RemoveCommentsTest::test_returns_unicode tests/test_html.py::RemoveTagsTest::test_keep_argument tests/test_html.py::RemoveTagsTest::test_remove_empty_tags tests/test_html.py::RemoveTagsTest::test_remove_tags tests/test_html.py::RemoveTagsTest::test_remove_tags_with_attributes tests/test_html.py::RemoveTagsTest::test_remove_tags_without_tags tests/test_html.py::RemoveTagsTest::test_returns_unicode tests/test_html.py::RemoveTagsTest::test_uppercase_tags tests/test_html.py::RemoveTagsWithContentTest::test_empty_tags tests/test_html.py::RemoveTagsWithContentTest::test_returns_unicode tests/test_html.py::RemoveTagsWithContentTest::test_with_tags tests/test_html.py::RemoveTagsWithContentTest::test_without_tags tests/test_html.py::ReplaceEscapeCharsTest::test_returns_unicode tests/test_html.py::ReplaceEscapeCharsTest::test_with_escape_chars tests/test_html.py::ReplaceEscapeCharsTest::test_without_escape_chars tests/test_html.py::UnquoteMarkupTest::test_returns_unicode tests/test_html.py::UnquoteMarkupTest::test_unquote_markup tests/test_html.py::GetBaseUrlTest::test_attributes_before_href tests/test_html.py::GetBaseUrlTest::test_get_base_url tests/test_html.py::GetBaseUrlTest::test_get_base_url_latin1 tests/test_html.py::GetBaseUrlTest::test_get_base_url_latin1_percent tests/test_html.py::GetBaseUrlTest::test_get_base_url_utf8 tests/test_html.py::GetBaseUrlTest::test_no_scheme_url tests/test_html.py::GetBaseUrlTest::test_relative_url_with_absolute_path tests/test_html.py::GetBaseUrlTest::test_tag_name tests/test_html.py::GetMetaRefreshTest::test_commented_meta_refresh tests/test_html.py::GetMetaRefreshTest::test_entities_in_redirect_url tests/test_html.py::GetMetaRefreshTest::test_float_refresh_intervals tests/test_html.py::GetMetaRefreshTest::test_get_meta_refresh tests/test_html.py::GetMetaRefreshTest::test_html_comments_with_uncommented_meta_refresh tests/test_html.py::GetMetaRefreshTest::test_inside_noscript tests/test_html.py::GetMetaRefreshTest::test_inside_script tests/test_html.py::GetMetaRefreshTest::test_leading_newline_in_url tests/test_html.py::GetMetaRefreshTest::test_multiline tests/test_html.py::GetMetaRefreshTest::test_nonascii_url_latin1 tests/test_html.py::GetMetaRefreshTest::test_nonascii_url_latin1_query tests/test_html.py::GetMetaRefreshTest::test_nonascii_url_utf8 tests/test_html.py::GetMetaRefreshTest::test_relative_redirects tests/test_html.py::GetMetaRefreshTest::test_tag_name tests/test_html.py::GetMetaRefreshTest::test_without_url