Untitled

let s_html = "<html><div>Hello</div></html>";;

let body = (Netsendmail.wrap_attachment
              ~content_type:("text/html", [])
              (new Netmime.memory_mime_body s_html))::[]

let email = Netsendmail.wrap_mail
        ~from_addr:("You", "[email protected]")
        ~to_addrs:[("person", "[email protected]")]
        ~out_charset:`Enc_utf8
        ~subject:"Test"
               (
                Netsendmail.wrap_parts
                ~content_type:("multipart/mixed",[])
                body);;

Netsendmail.sendmail ~mailer:"/usr/sbin/sendmail" email