diff --git a/docs/rh-log.txt b/docs/rh-log.txt
index 5b6fd81a8..0b70e6be5 100644
--- a/docs/rh-log.txt
+++ b/docs/rh-log.txt
@@ -1,4 +1,5 @@
 August 10, 2009
+- Fixed: P_TestMobjZ() needs THRUSPECIES and THRUACTORS checks, too.
 - Fixed: The UDMF loader did not initialize the sectors' sectornum property.
 
 August 10, 2009  (Changes by Graf Zahl)
diff --git a/src/p_map.cpp b/src/p_map.cpp
index abd4d3f66..595f2bad2 100644
--- a/src/p_map.cpp
+++ b/src/p_map.cpp
@@ -1385,6 +1385,14 @@ bool P_TestMobjZ (AActor *actor, bool quick, AActor **pOnmobj)
 		{
 			continue;
 		}
+		if ((actor->flags2 | thing->flags2) & MF2_THRUACTORS)
+		{
+			continue;
+		}
+		if ((actor->flags6 & MF6_THRUSPECIES) && (thing->GetSpecies() == actor->GetSpecies()))
+		{
+			continue;
+		}
 		if (!(thing->flags & MF_SOLID))
 		{ // Can't hit thing
 			continue;