diff --git a/docs/rh-log.txt b/docs/rh-log.txt
index bf41a44ac6..534f1f4cd4 100644
--- a/docs/rh-log.txt
+++ b/docs/rh-log.txt
@@ -1,3 +1,10 @@
+September 5, 2008
+- The garbage collector now has an opportunity to step each time individual
+  thinkers tick, not just once every game tick. This more closely follows
+  the original Lua behavior. This change was made because, in cases of
+  extremely large and frequent memory allocations, the collector may not run
+  fast enough if it only has a chance to execute once per tick.
+
 September 4, 2008
 - Fixed: The "same level" dmflag did not work.
 - Changed the nextlevel global var to an FString.
diff --git a/src/dobjgc.cpp b/src/dobjgc.cpp
index ac59004e17..fedd5076d3 100644
--- a/src/dobjgc.cpp
+++ b/src/dobjgc.cpp
@@ -126,6 +126,8 @@ IMPLEMENT_CLASS(DSectorMarker)
 
 // EXTERNAL DATA DECLARATIONS ----------------------------------------------
 
+extern DThinker *NextToThink;
+
 // PUBLIC DATA DEFINITIONS -------------------------------------------------
 
 namespace GC
@@ -327,6 +329,8 @@ static void MarkRoot()
 	Mark(bglobal.firstthing);
 	Mark(bglobal.body1);
 	Mark(bglobal.body2);
+	// NextToThink must not be freed while thinkers are ticking.
+	Mark(NextToThink);
 	// Mark soft roots.
 	if (SoftRoots != NULL)
 	{
diff --git a/src/dthinker.cpp b/src/dthinker.cpp
index ecac8933ff..36003aa98e 100644
--- a/src/dthinker.cpp
+++ b/src/dthinker.cpp
@@ -46,7 +46,7 @@ extern int BotWTG;
 
 IMPLEMENT_CLASS (DThinker)
 
-static DThinker *NextToThink;
+DThinker *NextToThink;
 
 FThinkerList DThinker::Thinkers[MAX_STATNUM+2];
 FThinkerList DThinker::FreshThinkers[MAX_STATNUM+1];
@@ -463,6 +463,7 @@ int DThinker::TickThinkers (FThinkerList *list, FThinkerList *dest)
 		if (!(node->ObjectFlags & OF_EuthanizeMe))
 		{ // Only tick thinkers not scheduled for destruction
 			node->Tick ();
+			GC::CheckGC();
 		}
 		node = NextToThink;
 	}