diff --git a/doc/UltiSnips.txt b/doc/UltiSnips.txt
index 3a80297..5a0ad6b 100644
--- a/doc/UltiSnips.txt
+++ b/doc/UltiSnips.txt
@@ -1235,6 +1235,10 @@ The options can be any combination of >
    i    - case insensitive
           By default, regular expression matching is case sensitive. With this
           option, matching is done without regard to case.
+   m    - multiline
+          By default, if you select multiple lines, transformations are made
+          on them entirely as a whole single line string. With this option you
+          can work with multi line strings.
    a    - ascii conversion
           By default, transformation are made on the raw utf-8 string. With
           this option, matching is done on the corresponding ASCII string