diff --git a/src/lib.rs b/src/lib.rs
index 1f39379e2..5d49b7fc6 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -249,13 +249,19 @@ macro_rules! iproduct {
     (@flatten $I:expr, $J:expr, $($K:expr,)*) => (
         $crate::iproduct!(@flatten $crate::cons_tuples($crate::iproduct!($I, $J)), $($K,)*)
     );
-    ($I:expr) => (
-        $crate::__std_iter::IntoIterator::into_iter($I)
+    () => (
+        $crate::__std_iter::once(())
     );
-    ($I:expr, $J:expr) => (
-        $crate::Itertools::cartesian_product($crate::iproduct!($I), $crate::iproduct!($J))
+    ($I:expr $(,)?) => (
+        $crate::__std_iter::IntoIterator::into_iter($I).map(|elt| (elt,))
     );
-    ($I:expr, $J:expr, $($K:expr),+) => (
+    ($I:expr, $J:expr $(,)?) => (
+        $crate::Itertools::cartesian_product(
+            $crate::__std_iter::IntoIterator::into_iter($I),
+            $crate::__std_iter::IntoIterator::into_iter($J),
+        )
+    );
+    ($I:expr, $J:expr, $($K:expr),+ $(,)?) => (
         $crate::iproduct!(@flatten $crate::iproduct!($I, $J), $($K,)+)
     );
 }
diff --git a/tests/macros_hygiene.rs b/tests/macros_hygiene.rs
index d1111245d..20b59fba8 100644
--- a/tests/macros_hygiene.rs
+++ b/tests/macros_hygiene.rs
@@ -1,5 +1,6 @@
 #[test]
 fn iproduct_hygiene() {
+    let _ = itertools::iproduct!();
     let _ = itertools::iproduct!(0..6);
     let _ = itertools::iproduct!(0..6, 0..9);
     let _ = itertools::iproduct!(0..6, 0..9, 0..12);
diff --git a/tests/test_core.rs b/tests/test_core.rs
index 45a8df438..db77a1e3e 100644
--- a/tests/test_core.rs
+++ b/tests/test_core.rs
@@ -18,6 +18,23 @@ use crate::it::Itertools;
 use core::iter;
 use itertools as it;
 
+#[test]
+fn product0() {
+    let mut prod = iproduct!();
+    assert_eq!(prod.next(), Some(()));
+    assert!(prod.next().is_none());
+}
+
+#[test]
+fn iproduct1() {
+    let s = "αβ";
+
+    let mut prod = iproduct!(s.chars());
+    assert_eq!(prod.next(), Some(('α',)));
+    assert_eq!(prod.next(), Some(('β',)));
+    assert!(prod.next().is_none());
+}
+
 #[test]
 fn product2() {
     let s = "αβ";