diff --git a/src/calibre/ebooks/pml/pmlconverter.py b/src/calibre/ebooks/pml/pmlconverter.py
index 166695ff5c..3a4454725a 100644
--- a/src/calibre/ebooks/pml/pmlconverter.py
+++ b/src/calibre/ebooks/pml/pmlconverter.py
@@ -216,7 +216,7 @@ class PML_HTMLizer(object):
                 html = re.sub(r'(?u)%s\s*%s' % (open % '.*?', close), '', html)
             else:
                 html = re.sub(r'(?u)%s\s*%s' % (open, close), '', html)
-        html = re.sub(r'<p>\s*</p>', '', html)
+        html = re.sub(r'(?imu)<p>\s*</p>', '', html)
         return html
 
     def start_line(self):