diff --git a/core/include/msg.h b/core/include/msg.h
index 203b303ded..d18499ddbe 100644
--- a/core/include/msg.h
+++ b/core/include/msg.h
@@ -60,7 +60,7 @@ typedef struct msg {
 
 
 /**
- * @brief Send a message.
+ * @brief Send a message. (blocking)
  *
  * This function sends a message to another thread. The ``msg_t`` structure has
  * to be allocated (e.g. on the stack) before calling the function and can be
@@ -70,16 +70,33 @@ typedef struct msg {
  * @param[in] m             Pointer to preallocated ``msg_t`` structure, must
  *                          not be NULL.
  * @param[in] target_pid    PID of target thread
- * @param[in] block         If not 0 and receiver is not receive-blocked,
- *                          function will block. If not, function returns.
+ *
+ * @return 1, if sending was successful (message delivered directly or to a
+ *            queue)
+ * @return 0, if called from ISR and receiver cannot receive the message now
+ *            (it is not waiting or it's message queue is full)
+ * @return -1, on error (invalid PID)
+ */
+int msg_send(msg_t *m, kernel_pid_t target_pid);
+
+
+/**
+ * @brief Send a message. (non-blocking)
+ *
+ * This function sends a message to another thread. The ``msg_t`` structure has
+ * to be allocated (e.g. on the stack) before calling the function and can be
+ * freed afterwards. This function will never block.
+ *
+ * @param[in] m             Pointer to preallocated ``msg_t`` structure, must
+ *                          not be NULL.
+ * @param[in] target_pid    PID of target thread
  *
  * @return 1, if sending was successful (message delivered directly or to a
  *         queue)
- * @return 0, if receiver is not waiting or has a full message queue and
- *         ``block == 0``
+ * @return 0, if receiver is not waiting or has a full message queue
  * @return -1, on error (invalid PID)
  */
-int msg_send(msg_t *m, kernel_pid_t target_pid, bool block);
+int msg_try_send(msg_t *m, kernel_pid_t target_pid);
 
 
 /**
diff --git a/core/msg.c b/core/msg.c
index ec16e94cab..1d89344e3d 100644
--- a/core/msg.c
+++ b/core/msg.c
@@ -37,6 +37,7 @@
 #include "thread.h"
 
 static int _msg_receive(msg_t *m, int block);
+static int _msg_send(msg_t *m, kernel_pid_t target_pid, bool block);
 
 
 static int queue_msg(tcb_t *target, msg_t *m)
@@ -51,7 +52,15 @@ static int queue_msg(tcb_t *target, msg_t *m)
     return 0;
 }
 
-int msg_send(msg_t *m, kernel_pid_t target_pid, bool block)
+int msg_send(msg_t *m, kernel_pid_t target_pid) {
+    return _msg_send(m, target_pid, true);
+}
+
+int msg_try_send(msg_t *m, kernel_pid_t target_pid) {
+    return _msg_send(m, target_pid, false);
+}
+
+static int _msg_send(msg_t *m, kernel_pid_t target_pid, bool block)
 {
     if (inISR()) {
         return msg_send_int(m, target_pid);