diff --git a/CHANGELOG.md b/CHANGELOG.md
index e86b28e7..40bb04bf 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,9 @@
 
 * Support interpolation in loud comments.
 
+* Fix a bug where even valid semicolons and exclamation marks in custom property
+  values were disallowed.
+
 * Disallow invalid function names.
 
 * Support terse mixin syntax in the indented syntax.
diff --git a/lib/src/parse/parser.dart b/lib/src/parse/parser.dart
index c8a75594..da1434da 100644
--- a/lib/src/parse/parser.dart
+++ b/lib/src/parse/parser.dart
@@ -230,7 +230,9 @@ abstract class Parser {
 
         case $exclamation:
         case $semicolon:
-          break loop;
+          if (brackets.isEmpty) break loop;
+          buffer.writeCharCode(scanner.readChar());
+          break;
 
         case $u:
         case $U:
diff --git a/lib/src/parse/stylesheet.dart b/lib/src/parse/stylesheet.dart
index 170034ef..97dda6dd 100644
--- a/lib/src/parse/stylesheet.dart
+++ b/lib/src/parse/stylesheet.dart
@@ -2289,7 +2289,9 @@ abstract class StylesheetParser extends Parser {
 
         case $exclamation:
         case $semicolon:
-          break loop;
+          if (brackets.isEmpty) break loop;
+          buffer.writeCharCode(scanner.readChar());
+          break;
 
         case $u:
         case $U: