diff --git a/dumux/flux/box/maxwellstefanslaw.hh b/dumux/flux/box/maxwellstefanslaw.hh
index 38c1027cb67d0b2fadbc740b8eab9343bae0288f..8004d2936116e5a3bd33969347f9ffcf6a5db5a1 100644
--- a/dumux/flux/box/maxwellstefanslaw.hh
+++ b/dumux/flux/box/maxwellstefanslaw.hh
@@ -159,7 +159,7 @@ private:
             auto tinInside = getDiffusionCoefficient(phaseIdx, compIIdx, numComponents-1, problem, element, insideVolVars, fvGeometry.scv(insideScvIdx));
             tinInside = EffDiffModel::effectiveDiffusivity(insideVolVars.porosity(), insideVolVars.saturation(phaseIdx), tinInside);
             auto tinOutside = getDiffusionCoefficient(phaseIdx, compIIdx, numComponents-1, problem, element, outsideVolVars, fvGeometry.scv(outsideScvIdx));
-            tinOutside = EffDiffModel::effectiveDiffusivity(insideVolVars.porosity(), insideVolVars.saturation(phaseIdx), tinOutside);
+            tinOutside = EffDiffModel::effectiveDiffusivity(outsideVolVars.porosity(), outsideVolVars.saturation(phaseIdx), tinOutside);
 
                             // scale by extrusion factor
             tinInside *= insideVolVars.extrusionFactor();
@@ -183,7 +183,7 @@ private:
                 auto tijInside = getDiffusionCoefficient(phaseIdx, compIIdx, compJIdx, problem, element, insideVolVars, fvGeometry.scv(insideScvIdx));
                 tijInside = EffDiffModel::effectiveDiffusivity(insideVolVars.porosity(), insideVolVars.saturation(phaseIdx), tijInside);
                 auto tijOutside = getDiffusionCoefficient(phaseIdx, compIIdx, compJIdx, problem, element, outsideVolVars, fvGeometry.scv(outsideScvIdx));
-                tijOutside = EffDiffModel::effectiveDiffusivity(insideVolVars.porosity(), outsideVolVars.saturation(phaseIdx), tijOutside);
+                tijOutside = EffDiffModel::effectiveDiffusivity(outsideVolVars.porosity(), outsideVolVars.saturation(phaseIdx), tijOutside);
 
                 // scale by extrusion factor
                 tijInside *= insideVolVars.extrusionFactor();