diff --git a/doc/fontconfig-user.sgml b/doc/fontconfig-user.sgml
index c6ab856..f29cfe0 100644
--- a/doc/fontconfig-user.sgml
+++ b/doc/fontconfig-user.sgml
@@ -627,6 +627,29 @@ This is an example of a system-wide configuration file
 	<family>monospace</family>
 	<prefer><family>Andale Mono</family></prefer>
 </alias>
+
+<--
+	The example of the requirements of OR operator;
+	If the 'family' contains 'Courier New' OR 'Courier'
+	add 'monospace' as the alternative
+-->
+<match target="pattern">
+	<test name="family" mode="eq">
+		<string>Courier New</string>
+	</test>
+	<edit name="family" mode="prepend">
+		<string>monospace</string>
+	</edit>
+</match>
+<match target="pattern">
+	<test name="family" mode="eq">
+		<string>Courier</string>
+	</test>
+	<edit name="family" mode="prepend">
+		<string>monospace</string>
+	</edit>
+</match>
+
 </fontconfig>
     </programlisting>
   </refsect2>
diff --git a/src/fcxml.c b/src/fcxml.c
index f027270..d92cbcc 100644
--- a/src/fcxml.c
+++ b/src/fcxml.c
@@ -1590,6 +1590,7 @@ FcParseAlias (FcConfigParse *parse)
 	case FcVStackFamily:
 	    if (family)
 	    {
+		FcConfigMessage (parse, FcSevereWarning, "Having multiple <family> in <alias> isn't supported and may not works as expected");
 		new = FcExprCreateOp (parse->config, vstack->u.expr, FcOpComma, family);
 		if (!new)
 		    FcConfigMessage (parse, FcSevereError, "out of memory");
@@ -2204,6 +2205,10 @@ FcParseTest (FcConfigParse *parse)
 	FcConfigMessage (parse, FcSevereWarning, "missing test expression");
 	return;
     }
+    if (expr->op == FcOpComma)
+    {
+	FcConfigMessage (parse, FcSevereWarning, "Having multiple values in <test> isn't supported and may not works as expected");
+    }
     test = FcTestCreate (parse, kind, qual, name, FC_OP (compare, flags), expr);
     if (!test)
     {