diff --git a/mithril.js b/mithril.js
index be86fc48..eeff8b31 100644
--- a/mithril.js
+++ b/mithril.js
@@ -857,7 +857,7 @@ Mithril = m = new function app(window, undefined) {
 					else options.onerror({type: "error", target: xhr})
 				}
 			}
-			if (options.serialize == JSON.stringify && options.method != "GET") {
+			if (options.serialize == JSON.stringify && options.data && options.method != "GET") {
 				xhr.setRequestHeader("Content-Type", "application/json; charset=utf-8")
 			}
 			if (typeof options.config == "function") {
@@ -865,7 +865,7 @@ Mithril = m = new function app(window, undefined) {
 				if (maybeXhr != null) xhr = maybeXhr
 			}
 
-			xhr.send(options.method == "GET" ? "" : options.data)
+			xhr.send(options.method == "GET" || !options.data ? "" : options.data)
 			return xhr
 		}
 	}