diff --git a/mode/html.py b/mode/html.py
index 94a2e07..d5cc047 100644
--- a/mode/html.py
+++ b/mode/html.py
@@ -65,6 +65,9 @@ class HtmlCheckSpelling(method.Method):
         # -x   no backup file
         # -M   show context menu
         # -H   treat input document as HTML
+        if w.buffer.changed():
+            w.set_error("There are unsaved changes; please save first.")
+            return
         w.application.run_external('ispell', '-x', '-M', '-H', w.buffer.path)
         if w.buffer.changed_on_disk():
             w.buffer.reload()