diff --git a/ChangeLog.rst b/ChangeLog.rst
index afdb277..b7d21c6 100644
--- a/ChangeLog.rst
+++ b/ChangeLog.rst
@@ -23,6 +23,13 @@ New Features
   a name for the rule as a second positional argument.
 
 
+Bugs Fixed
+----------
+
+- Fix :py:meth:`Rule.isomorphicLeftRight`/:cpp:func:`rule::Rule::isomorphicLeftRight`,
+  it was completely broken.
+
+
 v0.16.0 (2024-06-18)
 ====================
 
diff --git a/libs/libmod/src/mod/lib/Rules/Real.cpp b/libs/libmod/src/mod/lib/Rules/Real.cpp
index 8323762..6fdffb4 100644
--- a/libs/libmod/src/mod/lib/Rules/Real.cpp
+++ b/libs/libmod/src/mod/lib/Rules/Real.cpp
@@ -8,6 +8,7 @@
 #include <mod/lib/GraphMorphism/LabelledMorphism.hpp>
 #include <mod/lib/GraphMorphism/VF2Finder.hpp>
 #include <mod/lib/LabelledGraph.hpp>
+#include <mod/lib/LabelledFilteredGraph.hpp>
 #include <mod/lib/IO/IO.hpp>
 #include <mod/lib/Rules/IO/DepictionData.hpp>
 #include <mod/lib/Rules/Properties/Molecule.hpp>
@@ -194,15 +195,15 @@ std::size_t Real::monomorphism(const Real &rDom,
 bool Real::isomorphicLeftRight(const Real &rDom, const Real &rCodom, LabelSettings labelSettings) {
 	auto mrLeft = jla_boost::GraphMorphism::makeLimit(1);
 	lib::GraphMorphism::morphismSelectByLabelSettings(
-			get_labelled_left(rDom.getDPORule()),
-			get_labelled_left(rCodom.getDPORule()),
+			LabelledFilteredGraph(get_labelled_left(rDom.getDPORule())),
+			LabelledFilteredGraph(get_labelled_left(rCodom.getDPORule())),
 			labelSettings,
 			lib::GraphMorphism::VF2Isomorphism(), std::ref(mrLeft));
 	if(mrLeft.getNumHits() == 0) return false;
 	auto mrRight = jla_boost::GraphMorphism::makeLimit(1);
 	lib::GraphMorphism::morphismSelectByLabelSettings(
-			get_labelled_right(rDom.getDPORule()),
-			get_labelled_right(rCodom.getDPORule()),
+			LabelledFilteredGraph(get_labelled_right(rDom.getDPORule())),
+			LabelledFilteredGraph(get_labelled_right(rCodom.getDPORule())),
 			labelSettings,
 			lib::GraphMorphism::VF2Isomorphism(), std::ref(mrRight));
 	return mrRight.getNumHits() == 1;
diff --git a/test/py/rule/850_isomorphismLeftRight.py b/test/py/rule/850_isomorphismLeftRight.py
index e735240..6d83dc6 100644
--- a/test/py/rule/850_isomorphismLeftRight.py
+++ b/test/py/rule/850_isomorphismLeftRight.py
@@ -1,23 +1,16 @@
 include("xxx_helpers.py")
 
-rId = Rule.fromGMLString("""rule [
-	ruleID "id"
-	context [
-		node [ id 0 label "A" ]
-		node [ id 1 label "B" ]
-	]
-]""")
-rSwap = Rule.fromGMLString("""rule [
-	ruleID "id"
-	left [
-		node [ id 0 label "A" ]
-		node [ id 1 label "B" ]
-	]
-	right [
-		node [ id 0 label "B" ]
-		node [ id 1 label "A" ]
-	]
-]""")
+rId = Rule.fromDFS("[A]0.[B]1>>[A]0.[B]1", "ID")
+rSwap = Rule.fromDFS("[A]0.[B]1>>[A]1.[B]0", "swap")
+assert rId.isomorphism(rSwap) == 0
+assert rId.isomorphicLeftRight(rSwap)
+
+commonChecks(rId)
+commonChecks(rSwap)
+
+
+rId = Rule.fromDFS("[A]0-[A]1.[A]10-[A]11>>[A]0-[A]1.[A]10-[A]11", "ID")
+rSwap = Rule.fromDFS("[A]0-[A]1.[A]10-[A]11>>[A]0-[A]10.[A]1-[A]11", "swap")
 assert rId.isomorphism(rSwap) == 0
 assert rId.isomorphicLeftRight(rSwap)