diff --git a/accessible/src/base/nsAccessible.cpp b/accessible/src/base/nsAccessible.cpp
index d697411ab11..232f1d46181 100644
--- a/accessible/src/base/nsAccessible.cpp
+++ b/accessible/src/base/nsAccessible.cpp
@@ -1639,6 +1639,14 @@ nsresult nsAccessible::AppendFlatStringFromContentNode(nsIContent *aContent, nsA
 
 nsresult nsAccessible::AppendFlatStringFromSubtree(nsIContent *aContent, nsAString *aFlatString)
 {
+  static nsIContent *startContent = nsnull;
+  // never run into the same content node, to prevent infinite recursion
+  if (startContent == aContent) {
+    return NS_OK;
+  }
+  if (!startContent) {
+    startContent = aContent;
+  }
   nsresult rv = AppendFlatStringFromSubtreeRecurse(aContent, aFlatString);
   if (NS_SUCCEEDED(rv) && !aFlatString->IsEmpty()) {
     nsAString::const_iterator start, end;
@@ -1653,6 +1661,10 @@ nsresult nsAccessible::AppendFlatStringFromSubtree(nsIContent *aContent, nsAStri
       aFlatString->Truncate(aFlatString->Length() - spacesToTruncate);
   }
 
+  if (startContent == aContent) {
+    // we are leaving the original invoking
+    startContent = nsnull;
+  }
   return rv;
 }