diff --git a/src/eval.c b/src/eval.c
index 139f3f3abf1..eb08972bc67 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -658,6 +658,9 @@ for the variable is `*'.")
 {
   Lisp_Object documentation;
   
+  if (!SYMBOLP (variable))
+      return Qnil;
+
   documentation = Fget (variable, Qvariable_documentation);
   if (INTEGERP (documentation) && XINT (documentation) < 0)
     return Qt;