diff --git a/spec/suites/MatchersSpec.js b/spec/suites/MatchersSpec.js
index ef26c95..c39f66b 100644
--- a/spec/suites/MatchersSpec.js
+++ b/spec/suites/MatchersSpec.js
@@ -457,7 +457,10 @@ describe("jasmine.Matchers", function() {
     var expected = match(function() {
       throw new Error("Fake Error");
     });
+
     expect(expected.toThrow()).toEqual(true);
+    expect(expected.not.toThrow()).toEqual(false);
+
     expect(expected.toThrow("Fake Error")).toEqual(true);
     expect(expected.toThrow(new Error("Fake Error"))).toEqual(true);
 
diff --git a/src/Matchers.js b/src/Matchers.js
index 0e75bfb..a4d8998 100644
--- a/src/Matchers.js
+++ b/src/Matchers.js
@@ -297,7 +297,7 @@ jasmine.Matchers.prototype.toThrow = function(expected) {
 
   this.message = function() {
     if (exception && (expected === jasmine.undefined || !this.env.equals_(exception.message || exception, expected.message || expected))) {
-      return ["Expected function to throw", expected.message || expected, ", but it threw", exception.message || exception].join(' ');
+      return ["Expected function to throw", expected ? expected.message || expected : " an exception", ", but it threw", exception.message || exception].join(' ');
     } else {
       return "Expected function to throw an exception.";
     }