Index: typo3/sysext/cms/tslib/class.tslib_content.php
===================================================================
--- typo3/sysext/cms/tslib/class.tslib_content.php	(revision 4715)
+++ typo3/sysext/cms/tslib/class.tslib_content.php	(working copy)
@@ -5666,7 +5666,7 @@
 					$lastDotLabel = $lastDotLabel ? $lastDotLabel : '(dot)';
 					$spamProtectedMailAddress = preg_replace('/\.([^\.]+)$/', $lastDotLabel.'$1', $spamProtectedMailAddress);
 				}
-				$linktxt = str_replace($mailAddress, $spamProtectedMailAddress, $linktxt);
+				$linktxt = str_ireplace($mailAddress, $spamProtectedMailAddress, $linktxt);
 			}
 		} else {
 			$mailToUrl = $GLOBALS['TSFE']->absRefPrefix.$GLOBALS['TSFE']->config['mainScript'].$initP.'&jumpurl='.rawurlencode($mailToUrl).$GLOBALS['TSFE']->getMethodUrlIdToken;