diff --git a/dibi/dibi.php b/dibi/dibi.php
index aff38034..609fb650 100644
--- a/dibi/dibi.php
+++ b/dibi/dibi.php
@@ -638,9 +638,6 @@ class dibi
 	 */
 	public static function addSubst($expr, $subst)
 	{
-		if ($expr === '') {
-			trigger_error(__METHOD__ . ': empty substitutions will probably be deprecated.', E_USER_NOTICE);
-		}
 		self::$substs[$expr] = $subst;
 	}
 
@@ -656,7 +653,7 @@ class dibi
 		if ($expr === TRUE) {
 			self::$substs = array();
 		} else {
-			unset(self::$substs[$expr]);
+			unset(self::$substs[':'.$expr.':']);
 		}
 	}
 
diff --git a/examples/using-substitutions.php b/examples/using-substitutions.php
index 47f0e893..a87c94ae 100644
--- a/examples/using-substitutions.php
+++ b/examples/using-substitutions.php
@@ -26,6 +26,16 @@ dibi::test("SELECT * FROM [:blog:items]");
 
 
 
+// create new substitution :: (empty)  ==>  my_
+dibi::addSubst('', 'my_');
+
+dibi::test("UPDATE ::table SET [text]='Hello World'");
+// -> UPDATE my_table SET [text]='Hello World'
+
+
+
+
+
 // create substitutions using fallback callback
 function substFallBack($expr)
 {