diff --git a/doc/hg.1.txt b/doc/hg.1.txt
--- a/doc/hg.1.txt
+++ b/doc/hg.1.txt
@@ -251,11 +251,18 @@ identify::
 import [-p <n> -b <base> -f] <patches>::
     Import a list of patches and commit them individually.
 
+    If a patch looks like a mail message (its first line starts with
+    "From " or looks like an RFC822 header), it will not be applied
+    unless the -m option is used.  The importer neither parses nor
+    discards mail headers, so use -m only to override the "mailness"
+    safety check, not to import a real mail message.
+
     options:
     -p, --strip <n>   directory strip option for patch. This has the same
                       meaning as the corresponding patch option
     -b <path>         base directory to read patches from
     -f, --force	      skip check for outstanding uncommitted changes
+    -m, --mail-like   apply a patch that appears to be a mail message
 
     aliases: patch