If you are sending emails out of SAP which contains sensitive data such as usernames and passwords, you may not want any user with access to the sap transaction SOST to view these details. In order to do this you could possibly delete the entries out of the SAP table where these are stored. A better method would be to change the abap code in the program which sends the email so that it sets the emails as private or confidential. If this is done anyone who tries to view the emails via SAP tcode SOST will get a restricted access message, saying that the email can not be viewed as it is confidential.
In-order to do this you simply have to set the SENSITIVTY field within the document_data parameter to the correct value.
document-SENSITIVTY = 'P'. "P equals Confidential
document-SENSITIVTY = 'E'. "E equals Private
* Populate the subject/generic message attributes w_doc_data-obj_langu = sy-langu. w_doc_data-obj_name = 'SAPRPT'. w_doc_data-obj_descr = 'Email Subject'. w_doc_data-sensitivty = 'P'. * Call the FM to post the message to SAPMAIL CALL FUNCTION 'SO_DOCUMENT_SEND_API1' EXPORTING document_data = w_doc_data put_in_outbox = 'X' sender_address = ld_sender_address sender_address_type = ld_sender_address_type commit_work = 'X' IMPORTING sent_to_all = w_sent_all TABLES packing_list = t_packing_list contents_bin = t_attachment contents_txt = it_message receivers = t_receivers EXCEPTIONS too_many_receivers = 1 document_not_sent = 2 document_type_not_exist = 3 operation_no_authorization = 4 parameter_error = 5 x_error = 6 enqueue_error = 7 OTHERS = 8.