diff --git a/rust/macros/helpers.rs b/rust/macros/helpers.rs
index 8b5f9bc414d7ae..b4934c5fc396f3 100644
--- a/rust/macros/helpers.rs
+++ b/rust/macros/helpers.rs
@@ -69,11 +69,11 @@ pub(crate) fn expect_group(it: &mut token_stream::IntoIter) -> Group {
 }
 
 pub(crate) fn expect_string(it: &mut token_stream::IntoIter) -> String {
-    try_string(it).expect("Expected string")
+    try_string(it).expect("Expected string, maybe you used a byte string")
 }
 
 pub(crate) fn expect_string_ascii(it: &mut token_stream::IntoIter) -> String {
-    let string = try_string(it).expect("Expected string");
+    let string = try_string(it).expect("Expected string, maybe you used a byte string");
     assert!(string.is_ascii(), "Expected ASCII string");
     string
 }