diff --git a/ext/mbstring/mbstring.c b/ext/mbstring/mbstring.c
index 7a1e274fe74..cf8745c07c2 100644
--- a/ext/mbstring/mbstring.c
+++ b/ext/mbstring/mbstring.c
@@ -3446,7 +3446,7 @@ PHP_FUNCTION(mb_get_info)
 		if (lang != NULL && (name = (char *)mbfl_no_encoding2name(lang->mail_body_encoding)) != NULL) {
 			RETVAL_STRING(name, 1);
 		}
- 	} else if (!strcasecmp("illegalchars", typ)) {
+ 	} else if (!strcasecmp("illegal_chars", typ)) {
  		RETVAL_LONG(MBSTRG(illegalchars));
 	} else {
 		RETURN_FALSE;