Filed by Tyco International Ltd. and Mallinckrodt Inc.
                           Pursuant to Rule 425 under the Securities Act of 1933
                                        and deemed filed pursuant to Rule 14a-12
                                          of the Securities Exchange Act of 1934
                                              Subject Company: Mallinckrodt Inc.
                                                       Commission File No. 1-483


FOR IMMEDIATE RELEASE:
(Wednesday, June 28, 2000)


CONTACTS:
Tyco International
Investor Relations                            Media Relations
J. Brad McGee                                 Judith Czelusniak
Senior Vice President                         Senior Vice President, Corporate
Tyco International (US) Inc.                  Relations
(603) 778-9700                                Tyco International (US) Inc.
                                              (561) 988-7424

Mallinckrodt
Barbara Abbett
Vice President, Corporate Communications
Mallinckrodt Inc.
(314) 654-5230

                   TYCO INTERNATIONAL TO ACQUIRE MALLINCKRODT

          Acquisition Will Have Immediate Positive Impact on Earnings;
       Strengthens Tyco Healthcare's Leading Positions in Medical Devices

Pembroke,  Bermuda and St. Louis, MO, June 28, 2000 -- Tyco  International  Ltd.
(NYSE:  TYC;  LSE:  TYI;  BSX:  TYC), a  diversified  manufacturing  and service
company,  and Mallinckrodt Inc. (NYSE: MKG), a global healthcare company,  today
announced that they have entered into a definitive  agreement  pursuant to which
Tyco will  acquire  Mallinckrodt.  Mallinckrodt  shareholders  will receive Tyco
shares  valued at $47.50  for each share of  Mallinckrodt.  The  transaction  is
valued at approximately $4.2 billion.  Mallinckrodt,  which had 1999 revenues of
$2.6 billion,  has major positions in respiratory care,  diagnostic  imaging and
analgesic pharmaceuticals.

"Mallinckrodt  provides an excellent  strategic fit with Tyco  Healthcare,  with
complementary products,  services and geographic reach, as well as platforms for
future  growth,"  according to L. Dennis  Kozlowski,  Tyco's  Chairman and Chief
Executive Officer.



"The Mallinckrodt acquisition will be immediately accretive to Tyco's earnings,"
Mr.  Kozlowski  stated.  "It  offers  consolidation  opportunities  as  well  as
significant  manufacturing,  purchasing  and  distribution  synergies.  Our past
acquisitions  in Tyco  Healthcare  have  achieved  strong  top line  growth  and
operating efficiencies. We expect that the acquisition of Mallinckrodt also will
provide ongoing positive benefits to Tyco shareholders.

"Tyco has a strong  history of success in building  leadership  positions in the
healthcare  industry.  Tyco  Healthcare  has  grown  to be a  powerful  force in
disposable medical supplies and medical devices through previous acquisitions of
such industry brands as Kendall, United States Surgical, Auto Suture,  Sherwood,
Davis & Geck, Graphic Controls and ValleyLab. With the addition of Mallinckrodt,
Tyco Healthcare  will become the  second-largest  manufacturer,  distributor and
servicer of medical devices  worldwide,  and the market leader in bulk analgesic
pharmaceuticals," Mr. Kozlowski continued.

This acquisition will make Tyco Healthcare the leader in the fast growing global
respiratory care market, with products such as Mallinckrodt  endotracheal tubes,
Shiley tracheostomy tubes, Nellcor pulse oximeters, Puritan-Bennett ventilators,
and new  technologies  including  the recently  launched  OxiFirst  fetal oxygen
monitor  and  HELiOS  liquid  oxygen  system.  Mallinckrodt  also is a leader in
developing  new products in the growing  alternate  care markets for home oxygen
therapy,  sleep  therapy and portable  ventilation.  In the  diagnostic  imaging
market,  Mallinckrodt  has leadership  positions in imaging  contrast agents and
radiopharmaceuticals,  including Optiray and OptiMark.  Pharmaceutical  products
include  leadership  positions  in bulk  pharmaceuticals  and a rapidly  growing
dosage product line.

"The combined  strength of  Mallinckrodt's  products and Tyco's global sales and
service  organization  will allow Tyco Healthcare to leverage its  international
infrastructure  and enhance  penetration in key geographic  markets," stated Mr.
Kozlowski. "Mallinckrodt's strong positions in the respiratory,  pharmaceuticals
and diagnostic  imaging segments will provide Tyco with excellent  platforms for
future acquisitions and licensing agreements."

C.  Ray  Holman,   Chairman  of  the  Board  and  Chief  Executive   Officer  of
Mallinckrodt,  said,  "This  transaction  provides  exceptional  value  for  our
shareholders and allows  Mallinckrodt  shareholders to participate in the future
growth of Tyco.  There has been  substantial  consolidation  in our  industry in
recent years and we expect that to continue. We believe companies most likely to
succeed will have higher sales,  more leverage to operate  globally and a larger
basket of products to take to consolidated purchasers.  That's why our Board and
management team are very excited by the  opportunities the combination with Tyco
presents for both companies, our investors and our customers."

The transaction,  which will be accounted for as a purchase,  is contingent upon
customary  regulatory  review and  approval by  Mallinckrodt  shareholders.  The
Boards of Directors of both  companies have approved the  transaction,  which is
expected to be tax-free for the shareholders of Mallinckrodt. Under the terms of
the agreement, Mallinckrodt's shareholders will receive Tyco stock equivalent to
$47.50 for each share of  Mallinckrodt.  The number of Tyco shares they  receive
will be based on the volume  weighted  average  prices of Tyco shares on the New
York Stock Exchange composite tape for the five consecutive  trading days ending
on the day before the conditions to the acquisition are satisfied.



About Mallinckrodt
Mallinckrodt  is a global  manufacturer  and  distributor  of specialty  medical
products  designed to sustain  breathing,  diagnose  disease  and relieve  pain.
Mallinckrodt  does  business in more than 100  countries and had fiscal 1999 net
sales of $2.6 billion.  Mallinckrodt is the industry leader in respiratory  care
products, including those used for oxygen monitoring,  critical care ventilation
and service as well as airway  management  disposables.  In the  pharmaceuticals
market,  Mallinckrodt is the number one manufacturer of bulk narcotics and other
drug  chemicals,  and is the  world's  largest  producer of  acetaminophen.  The
growing dosage pharmaceutical  segment is focused on pain management,  addiction
therapy and attention deficit hyperactivity  disorder (ADHD).  Mallinckrodt also
provides laboratory and microelectronic  chemicals. Its imaging products include
contrast media used in x-ray,  magnetic resonance imaging (MRI),  computer axial
tomography   (C-T)  and   ultrasound   diagnostic   procedures.   Mallinckrodt's
radiopharmaceuticals  are used for diagnostic and therapeutic  nuclear  medicine
procedures.

About Tyco International
Tyco International Ltd. is a diversified manufacturing and service company. Tyco
is the world's  largest  manufacturer  and servicer of electrical and electronic
components  and undersea  telecommunications  systems,  and the world's  largest
manufacturer,  installer and provider of fire protection  systems and electronic
security  services.  Tyco has strong leadership  positions in disposable medical
products,  plastics and adhesives,  and is the world's  largest  manufacturer of
flow control  valves.  Tyco  operates in more than 80 countries and has expected
fiscal 2000 revenues of $28 billion.

Forward-Looking Information
This release contains certain "forward-looking statements" within the meaning of
the Private Securities Litigation Reform Act of 1995. These statements are based
on management's  current expectations and are subject to uncertainty and changes
in  circumstances.  Actual  results may vary  materially  from the  expectations
contained in the forward-looking  statements.  The forward-looking statements in
this release include statements addressing the following subjects: expected date
of closing the acquisition;  future financial and operating results;  and timing
and benefits of the acquisition.

The  following  factors,  among  others,  could cause  actual  results to differ
materially from those described in the forward-looking statements:  inability to
obtain,  or meet  conditions  imposed  for,  governmental  approvals  for Tyco's
acquisition of Mallinckrodt;  failure of the Mallinckrodt  shareholders to adopt
the agreement  providing for Tyco's  acquisition of Mallinckrodt;  the risk that
the businesses of Tyco and Mallinckrodt will not be integrated successfully; and
other economic, business, competitive and/or regulatory factors affecting Tyco's
and Mallinckrodt's businesses generally.

More  detailed  information  about  these  factors  is set forth in  Tyco's  and
Mallinckrodt's  filings with the Securities and Exchange  Commission,  including
Tyco's  Annual  Report on Form  10-K,  as  amended,  for the  fiscal  year ended
September  30, 1999,  Mallinckrodt's  Annual  Report on Form 10-K for the fiscal
year ended June 30, 1999, their most recent  Quarterly  Reports on Form 10-Q, as
amended,  and their Current Reports on Form 8-K. Tyco and Mallinckrodt are under
no obligation to (and expressly disclaim any such obligation to) update or alter
their forward-looking statements whether as a result of new information,  future
events or otherwise.

                            * * * * * * * * * * * * *



Investors    and   security    holders   are   advised   to   read   the   proxy
statement/prospectus  regarding the business combination  transaction referenced
in the foregoing information, when it becomes available, because it will contain
important  information.  The proxy  statement/prospectus  will be filed with the
Securities and Exchange  Commission by Tyco  International Ltd. and Mallinckrodt
Inc.  Investors  and  security  holders  may  obtain  a free  copy of the  proxy
statement/prospectus  (when  available)  and other  documents  filed by Tyco and
Mallinckrodt  at  the   Commission's   web  site  at   www.sec.gov.   The  proxy
statement/prospectus  and such other documents may also be obtained from Tyco or
from  Mallinckrodt  by directing  such request to Tyco  International  Ltd., The
Zurich Centre,  Second Floor, 90 Pitts Bay Road,  Pembroke HM 08, Bermuda,  tel:
(441) 292-8674;  or to Mallinckrodt Inc., Attention:  Corporate Secretary,  P.O.
Box 5840,  675  McDonnell  Boulevard,  St.  Louis,  MO 63134,  USA,  tel.  (314)
654-2000.

Mallinckrodt  and certain  other  persons  referred to below may be deemed to be
participants in the  solicitation of proxies of  Mallinckrodt's  shareholders to
adopt the  agreement  providing  for Tyco's  acquisition  of  Mallinckrodt.  The
participants  in this  solicitation  may include  the  directors  and  executive
officers of Mallinckrodt,  who may have an interest in the transaction including
as a result of holding shares or options of Mallinckrodt. A detailed list of the
names and  interests  of  Mallinckrodt's  directors  and  executive  officers is
contained in Mallinckrodt's  Proxy Statement for its 1999 Annual Meeting,  which
may be obtained without charge at the Commission's web site at www.sec.gov.


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