diff --git a/serial_posix.c b/serial_posix.c
index 982bc24..abe0d76 100644
--- a/serial_posix.c
+++ b/serial_posix.c
@@ -511,10 +511,13 @@ serial_flush (serial *device, int queue)
 	switch (queue) {
 	case SERIAL_QUEUE_INPUT:
 		flags = TCIFLUSH;
+		break;
 	case SERIAL_QUEUE_OUTPUT:
 		flags = TCOFLUSH;
+		break;
 	default:
 		flags = TCIOFLUSH;
+		break;
 	}
 
 	if (tcflush (device->fd, flags) != 0) {
diff --git a/serial_win32.c b/serial_win32.c
index fa2d6c1..bfb4f9d 100644
--- a/serial_win32.c
+++ b/serial_win32.c
@@ -355,10 +355,13 @@ serial_flush (serial* device, int queue)
 	switch (queue) {
 	case SERIAL_QUEUE_INPUT:
 		flags = PURGE_RXABORT | PURGE_RXCLEAR;
+		break;
 	case SERIAL_QUEUE_OUTPUT:
 		flags = PURGE_TXABORT | PURGE_TXCLEAR;
+		break;
 	default:
 		flags = PURGE_RXABORT | PURGE_RXCLEAR | PURGE_TXABORT | PURGE_TXCLEAR;
+		break;
 	}
 
 	if (!PurgeComm (device->hFile, flags)) {