Exhibit 21
MERCK & CO., INC. SUBSIDIARIES
as of 12/31/99

Each of the subsidiaries set forth below does business under the name
stated. A subsidiary of a subsidiary is indicated by indentation under the
immediate parent. All voting securities of the subsidiaries named are owned
directly or indirectly by the Company, except where otherwise indicated.

Country or State
Name of Incorporation
- ---- ----------------

Chibret A/S Denmark

Hangzhou MSD Pharmaceutical Company Limited/1/ China

International Indemnity Ltd. Bermuda

Johnson & Johnson - Merck Consumer Pharmaceuticals Company/1/ New Jersey

Laboratorios Prosalud S.A. Peru

MCM Vaccine Co./1/ Pennsylvania

Merck and Company, Incorporated Delaware
Merck SH Inc. Delaware

Merck Capital Investments, Inc. Delaware

Merck Capital Resources, Inc. Delaware
MSD Technology, L.P./1/ Delaware
Merck Finance Co., Inc. Delaware

Merck Enterprises Canada, Ltd. Canada

Merck Foreign Sales Corporation Ltd. Bermuda

Merck Hamilton, Inc. California

Merck Holdings, Inc. Delaware
Frosst Laboratories, Inc. Delaware
Frosst Portuguesa - Produtos Farmaceuticos, Lda. Portugal
Istituto Gentili S.p.A./Inc. Italy/Delaware
KBI Inc. Delaware
KBI Sub Inc. Delaware
KBI-E Inc. Delaware
KBI-P Inc. Delaware

Merck-Medco Holdings II Corp. Delaware
Cloverleaf International Holdings S.A. Luxembourg
Coordinated Patient Care Scandinavia AS Norway
Medco Holdings S. de R.L. de C.V. Mexico
Medco de Mexico Managed Care S. de R.L. de C.V. Mexico
Medco Servicios de Mexico, S. de R.L. de C.V. Mexico
Medidoc AB Sweden
Coordination Medicale et Pharmaceutique, S.A. France
Fontelabor-Produtos Farmaceuticos, Lda. Portugal
Merck Frosst Canada & Co. Canada
Maple Leaf Holdings SRL Barbados
Merck Sharp & Dohme (Australia) Pty. Limited Australia
AMRAD Pharmaceuticals Pty. Ltd./1/ Australia
Merck Sharp & Dohme B.V. Netherlands
Abello Farmacia, S.L./1/ Spain
Financiere MSD S.A.S. France
MSD (Nippon Holdings) BV Amsterdam
Chibret Pharmazeutische GmbH Germany
Laboratoires Martin-Johnson & Johnson-MSD S.A.S./1/ France
Laboratoires Merck Sharp & Dohme Chibret SNC France
Pasteur Merieux MSD Gestion S.A./1/ France
Pasteur Merieux MSD S.N.C./1/ France
Pasteur Merieux MSD A/S Denmark
Pasteur Merieux MSD GmbH Germany
Pasteur Merieux MSD Ltd. (UK) Great Britain
Pasteur Merieux MSD Ltd. (Ireland) Ireland
Pasteur Merieux MSD N.V. Belgium
Pasteur Merieux MSD S.A. Spain
Pasteur Merieux MSD S.p.A. Italy
Pasteur Vaccins S.A. France
Laboratorios Chibret, S.A. Spain
Laboratorios Frosst, S.A. Spain
Merck Sharp & Dohme GmbH Austria
Merck Sharp & Dohme (Italia) S.p.A. Italy
Abiogen Farma S.p.A. Italy
Istituto Di Richerche Di Biologia Molecolare S.p.A./1/ Italy
MSD (Proprietary) Limited South Africa
MSD Sharp & Dohme GmbH Germany
Dieckmann Arzneimittel GmbH Germany
Woelm Pharma GmbH & Co./1/ Germany
MSD Chibropharm GmbH Germany
MSD Unterstutzungskasse GmbH Germany
Varipharm Arzneimittel GmbH Germany
Sharp & Dohme, S.A. Spain
Merck Sharp & Dohme Chibret A.G. Switzerland
Merck Sharp & Dohme de Venezuela S.R.L. Venezuela

Merck Sharp & Dohme (Holdings) Limited Great Britain
Charles E. Frosst (U.K.) Limited Great Britain
Merck Sharp & Dohme Limited Great Britain
Johnson & Johnson MSD Consumer Pharmaceuticals/1/ Great Britain
Merck Sharp & Dohme Finance Europe Great Britain
Thomas Morson & Son Limited Great Britain
Merck Sharp & Dohme IDEA, Inc. Switzerland
Merck Sharp & Dohme (Sweden) A.B. Sweden
Merck Sharp & Dohme (Israel - 1996) Company Ltd. Israel
Merck Sharp & Dohme Trading & Service Limited Liability Company Hungary
MSD Ireland (Holdings) S.A. Luxembourg
Fabrica de Productos Quimicos y Farmaceuticos Abello, S.A. Spain
Fregenal Holdings S.A. Panama
Frosst Iberica, S.A. Spain
Laboratorios Quimico-Farmaceuticos Chibret, Lda. Portugal
Merck Sharp & Dohme de Espana, S.A. Spain
Merck Sharp & Dohme, Limitada Portugal
MSD Finance, B.V. Netherlands
MSD Overseas Manufacturing Co. Bermuda
Blue Jay Investments C.V. Netherlands
Merck Sharp & Dohme (Puerto Rico) Ltd. Bermuda
Merck Sharp & Dohme (Singapore) Ltd. Bermuda
MSD Ireland (Investment) Ltd. Bermuda
MSD Overseas Manufacturing Co. (Ireland) Ireland
Crosswinds B.V. Netherlands
Merck Sharp & Dohme (Ireland) Ltd. Bermuda
Tradewinds Manufacturing SRL Barbados
Neopharmed S.p.A. Italy
Ruskin Limited Bermuda
MSD (Norge) A/S Norway
Suomen MSD Oy Finland
Kiinteisto Oy Irmelinpesa/1/ Finland
Kiinteisto Oy Viistotie 11 Finland
Cuyahoga, C.A. Venezuela
Merck Sharp & Dohme Holdings de Mexico, S.A. de C.V. Mexico
Merck Sharp & Dohme de Mexico, S.A. de C.V. Mexico
Merck Sharp & Dohme (I.A.) Corp. Delaware
Merck Sharp & Dohme (Argentina) Inc. Delaware
MSD Korea Ltd. Korea/Delaware
Merck Sharp Dohme Ilaclari Limited Sirketi Turkey
Merck Sharp & Dohme Farmaceutica Ltda. Brazil
Prodome Quimica e Farmaceutica Ltda./1/ Brazil
Merck Sharp & Dohme (International) Limited Bermuda
Merck Sharp & Dohme (Asia) Limited Hong Kong
Merck Sharp & Dohme (China) Limited Hong Kong
Merck Sharp & Dohme S.A. France

Merck Sharp & Dohme International Services B.V. Netherlands
Merck Sharp & Dohme - Lebanon S.A.L. Lebanon
Merck Sharp & Dohme L.L.C. Russian Federation
Merck Sharp & Dohme (Middle East) Limited Cyprus
Merck Sharp & Dohme of Pakistan Limited Pakistan
Merck Sharp & Dohme Quimica de Puerto Rico, Inc. Delaware
Merck Sharp & Dohme S.A.R.L. Morocco
Merck Ventures, Inc. Delaware
MSD Lakemedel (Scandinavia) Aktiebolog Sweden
Prosalud Peruana S.A. Peru
STELLARx, Inc. Nevada
TELERx Marketing Inc. Pennsylvania

Merck Investment Co., Inc. Delaware

Merck Liability Management Company Delaware
Merck LMC Cash Management (Bermuda) Ltd. Bermuda
Merck LMC Cash Management, Inc. Delaware

Merck-Medco Managed Care, L.L.C. Delaware
CM Delaware Corporation Delaware
DM-MG, L.L.C. Delaware
MCCO Corp. New Jersey
Medco Containment Insurance Company of New Jersey New Jersey
Medco Containment Insurance Company of New York New York
Medco Containment Life Insurance Company Pennsylvania
Merck-Medco Managed Care of California, Inc. California
Merck-Medco Rx Services of Florida No. 2, L.C. Florida
Merck-Medco Rx Services of Florida, L.C. Florida
Merck-Medco Rx Services of Massachusetts, L.L.C. Massachusetts
Merck-Medco Rx Services of Nevada, Inc. Nevada
Merck-Medco Rx Services of New Jersey, L.L.C. New Jersey
Merck-Medco Rx Services of New York, L.L.C. New York
Merck-Medco Rx Services of Ohio, Ltd. Ohio
Merck-Medco Rx Services of Ohio No. 2, Ltd. Ohio
Merck-Medco Rx Services of Oklahoma, L.L.C. Oklahoma
Merck-Medco Rx Services of Pennsylvania, L.L.C. Pennsylvania
Merck-Medco Rx Services of Pennsylvania No. 2, L.L.C. Pennsylvania
Merck-Medco Rx Services of Texas, L.L.C. Texas
Merck-Medco Rx Services of Virginia, L.L.C. Virginia
Merck-Medco Rx Services of Washington, Inc. Washington
Merck-Medco Rx Services of Willingboro New Jersey, L.L.C. New Jersey
Mergerco Delaware No. 10, L.L.C. Delaware
MW Holdings, L.L.C. Delaware
NJRE, L.L.C. New Jersey
NRx Federal Corp. Delaware
National Rx Services, Inc. of Missouri Missouri

National Rx Services No. 3, Inc. of Ohio Ohio
New York PAID Independent Practice Association, L.L.C. New York
Paid Direct, Inc. Delaware
PAID Prescriptions, L.L.C. Nevada
Replacement Distribution Center, Inc. Ohio
The Institute for Effectiveness Research, L.L.C. Delaware
Systemed, L.L.C. Delaware
Systemed Pharmacy of Iowa, L.L.C. Delaware
Systemed Pharmacy of Ohio, Ltd. Ohio

Merck Resource Management, Inc. Delaware

Merck Sharp & Dohme (Europe) Inc. Delaware

Merck Sharp & Dohme Industria Quimica e Veterinaria Limitada Brazil

Merck Sharp & Dohme (New Zealand) Limited New Zealand

Merck Sharp & Dohme Overseas Finance N.V. Neth. Antilles

Merck Sharp & Dohme (Panama) S.A. Panama

Merck Sharp & Dohme Peru SRL Peru

Merck Sharp & Dohme (Philippines) Inc. Philippines

Merial Limited/LLC/1/ Great Britain/
Delaware
British United Turkeys Limited/1/ Great Britain
Turkey Research & Development Limited/1/ Great Britain

MSD International Holdings, Inc. Delaware
Banyu Pharmaceutical Company, Ltd./1/ Japan
Banyu-A.S.C. Co., Ltd. Japan
Nippon Merck-Banyu Co., Ltd. Japan

MSD (Japan) Co., Ltd. Japan

SIBIA Neurosciences, Inc. California

The O'Hare Group, Inc./1/ Delaware

______________________
/1/ own less than 100%