diff --git a/lisp/ob-core.el b/lisp/ob-core.el
index a63f77e9f..4ef210038 100644
--- a/lisp/ob-core.el
+++ b/lisp/ob-core.el
@@ -2521,6 +2521,7 @@ appropriate."
 (defun org-babel-number-p (string)
   "If STRING represents a number return its value."
   (if (and (string-match "^-?[0-9]*\\.?[0-9]*$" string)
+	   (string-match "[0-9]+" string)
            (= (length (substring string (match-beginning 0)
 				 (match-end 0)))
 	      (length string)))