diff --git a/alethzero/MainWin.cpp b/alethzero/MainWin.cpp
index c8c1732f6..e7f5cbbd9 100644
--- a/alethzero/MainWin.cpp
+++ b/alethzero/MainWin.cpp
@@ -970,6 +970,7 @@ void Main::on_data_textChanged()
 		}
 		else
 		{
+#if ETH_SERPENT
 			try
 			{
 				m_data = eth::asBytes(compile(src));
@@ -977,11 +978,14 @@ void Main::on_data_textChanged()
 			catch (string err)
 			{
 				errors.push_back("Serpent " + err);
+#endif
 				auto asmcode = eth::compileLLLToAsm(src, false);
 				auto asmcodeopt = eth::compileLLLToAsm(ui->data->toPlainText().toStdString(), true);
 				m_data = compileLLL(ui->data->toPlainText().toStdString(), true, &errors);
 				lll = "<h4>Opt</h4><pre>" + QString::fromStdString(asmcodeopt).toHtmlEscaped() + "</pre><h4>Pre</h4><pre>" + QString::fromStdString(asmcode).toHtmlEscaped() + "</pre>";
+#if ETH_SERPENT
 			}
+#endif
 		}
 		QString errs;
 		if (errors.size())