diff --git a/doc/regexp.rdoc b/doc/regexp.rdoc
index 2b6a870026..f3844d5729 100644
--- a/doc/regexp.rdoc
+++ b/doc/regexp.rdoc
@@ -620,6 +620,11 @@ Options may also be used with Regexp.new:
Regexp.new("abc # Comment", Regexp::EXTENDED) #=> /abc # Comment/x
Regexp.new("abc", Regexp::IGNORECASE | Regexp::MULTILINE) #=> /abc/mi
+ Regexp.new("abc", "i") #=> /abc/i
+ Regexp.new("abc", "m") #=> /abc/m
+ Regexp.new("abc # Comment", "x") #=> /abc # Comment/x
+ Regexp.new("abc", "im") #=> /abc/mi
+
== Free-Spacing Mode and Comments
As mentioned above, the x option enables free-spacing
diff --git a/re.c b/re.c
index 39d4fc046f..3e059b6287 100644
--- a/re.c
+++ b/re.c
@@ -3665,6 +3665,11 @@ str_to_option(VALUE str)
*
* Optional argument +options+ is one of the following:
*
+ * - A String of options:
+ *
+ * Regexp.new('foo', 'i') # => /foo/i
+ * Regexp.new('foo', 'im') # => /foo/im
+ *
* - The logical OR of one or more of the constants
* Regexp::EXTENDED, Regexp::IGNORECASE, and Regexp::MULTILINE:
*