diff --git a/grpc.go b/grpc.go
index 4af6571..5caa536 100644
--- a/grpc.go
+++ b/grpc.go
@@ -35,7 +35,7 @@ import (
 )
 
 const (
-	DefaultContentType = "application/grpc+proto"
+	DefaultContentType = "application/grpc"
 )
 
 /*