diff --git a/dumux/discretization/cellcentered/tpfa/fickslaw.hh b/dumux/discretization/cellcentered/tpfa/fickslaw.hh
index dd8bd863008bb7b9d732174b88a6087639de3068..e21792b7a5e360fa053cde38ffee137edd448b05 100644
--- a/dumux/discretization/cellcentered/tpfa/fickslaw.hh
+++ b/dumux/discretization/cellcentered/tpfa/fickslaw.hh
@@ -242,7 +242,8 @@ private:
             sumTi += outsideTi;
             sumXTi += outsideTi*outsideVolVars.moleFraction(phaseIdx, compIdx);
         }
-        return sumXTi/sumTi;
+
+        return sumTi > 0 ? sumXTi/sumTi : 0;
     }
 
     //! compute the density at branching facets for network grids as arithmetic mean