diff --git a/lib/multi_json.rb b/lib/multi_json.rb
index ca1e442d..9b0540a4 100644
--- a/lib/multi_json.rb
+++ b/lib/multi_json.rb
@@ -98,8 +98,10 @@ def load_adapter(new_adapter)
     when Class, Module
       new_adapter
     else
-      raise "Did not recognize your adapter specification. Please specify either a symbol or a class."
+      raise NameError
     end
+  rescue NameError, ::LoadError
+    raise ArgumentError, 'Did not recognize your adapter specification.'
   end
 
   # Decode a JSON string into Ruby.
diff --git a/spec/multi_json_spec.rb b/spec/multi_json_spec.rb
index 02310a2b..00e1cdd0 100644
--- a/spec/multi_json_spec.rb
+++ b/spec/multi_json_spec.rb
@@ -74,11 +74,15 @@
     end
 
     it 'is settable via a module' do
-      adapter =  Module.new
+      adapter = Module.new
       MultiJson.use adapter
       expect(MultiJson.adapter).to eq adapter
     end
 
+    it 'throws ArgumentError on bad input' do
+      expect{ MultiJson.use 'bad adapter' }.to raise_error(ArgumentError)
+    end
+
     context 'using one-shot parser' do
       before do
         MultiJson::Adapters::JsonPure.should_receive(:dump).once.and_return('dump_something')
@@ -159,4 +163,4 @@
       it_behaves_like 'JSON-like adapter', adapter
     end
   end
-end
+end
\ No newline at end of file