<Page>

                                                                    Exhibit 21.1

Medex, Inc. Significant and Other Subsidiaries

<Table>
<Caption>
- -------------------------------------------------------------------------------------
                                                     STATE OR OTHER JURISDICTION OF
      NAME OF SUBSIDIARY                            INCORPORATION OR ORGANIZATION
- -------------------------------------------------------------------------------------
                                               
MedVest Holdings Corp                             Ohio
- -------------------------------------------------------------------------------------
Medex, Inc.                                       Ohio
- -------------------------------------------------------------------------------------
Medex Medical, Inc.                               Ohio
- -------------------------------------------------------------------------------------
Medex Cardio-Pulmonary Inc.                       Ohio
- -------------------------------------------------------------------------------------
Medex de Mexico SA de CV                          Mexico
- -------------------------------------------------------------------------------------
Medex de Costa Rica, Ltda.                        Costa Rica
- -------------------------------------------------------------------------------------
Medex Canada, Inc.                                Canada
- -------------------------------------------------------------------------------------
Medex Japan KK                                    Japan
- -------------------------------------------------------------------------------------
Medex Medical France SARL                         France
- -------------------------------------------------------------------------------------
Medex EU SARL                                     Luxembourg
- -------------------------------------------------------------------------------------
Medex Financial SARL                              Luxembourg
- -------------------------------------------------------------------------------------
Medex Espana                                      Spain
- -------------------------------------------------------------------------------------
Medex Medical Ltd.                                United Kingdom
- -------------------------------------------------------------------------------------
Ashfield Medical Systems Ltd.                     Scotland
- -------------------------------------------------------------------------------------
Medex Medical                                     Switzerland
- -------------------------------------------------------------------------------------
Medex Do Brasil Productos Hospitalares, Ltda.     Brazil
- -------------------------------------------------------------------------------------
Medex Italia SRL                                  Italy
- -------------------------------------------------------------------------------------
Medex Holding GmbH                                Germany
- -------------------------------------------------------------------------------------
Medex Medical GmbH and Co KG                      Germany
- -------------------------------------------------------------------------------------
AS Medical GmbH                                   Germany
- -------------------------------------------------------------------------------------
</Table>