diff --git a/lib/timeout.rb b/lib/timeout.rb
index 11db4be973..572e90cafb 100644
--- a/lib/timeout.rb
+++ b/lib/timeout.rb
@@ -32,7 +32,9 @@ module Timeout
     def self.catch(*args)
       exc = new(*args)
       exc.instance_variable_set(:@thread, Thread.current)
-      ::Kernel.catch(exc) {yield exc}
+      catch_value = Object.new
+      exc.instance_variable_set(:@catch_value, catch_value)
+      ::Kernel.catch(catch_value) {yield exc}
     end
 
     def exception(*)
@@ -40,11 +42,11 @@ module Timeout
       if self.thread == Thread.current
         bt = caller
         begin
-          throw(self, bt)
+          throw(@catch_value, bt)
         rescue UncaughtThrowError
         end
       end
-      self
+      super
     end
   end
 
@@ -115,6 +117,7 @@ module Timeout
       begin
         bl.call(klass)
       rescue klass => e
+        message = e.message
         bt = e.backtrace
       end
     else
diff --git a/test/test_timeout.rb b/test/test_timeout.rb
index c57d90c063..71607ed680 100644
--- a/test/test_timeout.rb
+++ b/test/test_timeout.rb
@@ -80,6 +80,14 @@ class TestTimeout < Test::Unit::TestCase
     end
   end
 
+  def test_raise_with_message
+    bug17812 = '[ruby-core:103502] [Bug #17812]: Timeout::Error doesn\'t let two-argument raise() set a new message'
+    exc = Timeout::Error.new('foo')
+    assert_raise_with_message(Timeout::Error, 'bar', bug17812) do
+      raise exc, 'bar'
+    end
+  end
+
   def test_enumerator_next
     bug9380 = '[ruby-dev:47872] [Bug #9380]: timeout in Enumerator#next'
     e = (o=Object.new).to_enum