diff --git a/interpret.h b/interpret.h
index 4b140c2..5fb6d5e 100644
--- a/interpret.h
+++ b/interpret.h
@@ -134,7 +134,7 @@ top:
 
 		case Op_push_i:
 			m = pc->memory;
-			if (! do_traditional && (m->flags & INTLSTR) != 0) {
+			if (! do_traditional && (m->flags & INTLSTR) != 0 && m->stlen > 0) {
 				char *orig, *trans, save;
 
 				save = m->stptr[m->stlen];