diff --git a/lib/hoptoad_notifier/notice.rb b/lib/hoptoad_notifier/notice.rb
index 5c571d7..e4e3de7 100644
--- a/lib/hoptoad_notifier/notice.rb
+++ b/lib/hoptoad_notifier/notice.rb
@@ -226,14 +226,16 @@ def clean_unserializable_data_from(attribute)
     # Removes non-serializable data. Allowed data types are strings, arrays,
     # and hashes. All other types are converted to strings.
     # TODO: move this onto Hash
-    def clean_unserializable_data(data)
+    def clean_unserializable_data(data, stack = [])
+      return "[possible infinite recursion halted]" if stack.any?{|item| item == data.object_id }
+
       if data.respond_to?(:to_hash)
         data.to_hash.inject({}) do |result, (key, value)|
-          result.merge(key => clean_unserializable_data(value))
+          result.merge(key => clean_unserializable_data(value, stack + [data.object_id]))
         end
       elsif data.respond_to?(:to_ary)
         data.collect do |value|
-          clean_unserializable_data(value)
+          clean_unserializable_data(value, stack + [data.object_id])
         end
       else
         data.to_s
diff --git a/test/recursion_test.rb b/test/recursion_test.rb
new file mode 100644
index 0000000..c39d8be
--- /dev/null
+++ b/test/recursion_test.rb
@@ -0,0 +1,10 @@
+require File.dirname(__FILE__) + '/helper'
+
+class RecursionTest < Test::Unit::TestCase
+  should "not allow infinite recursion" do
+    hash = {:a => :a}
+    hash[:hash] = hash
+    notice = HoptoadNotifier::Notice.new(:parameters => hash)
+    assert_equal "[possible infinite recursion halted]", notice.parameters[:hash]
+  end
+end