PERCLOSE, INC.
                                ABBOTT LABORATORIES

                         SUPPLEMENT DATED NOVEMBER 11, 1999
                TO PROXY STATEMENT/PROSPECTUS DATED AUGUST 26, 1999


     In connection with the merger agreement among Abbott Laboratories, AL
Acquisition Corp. and Perclose, Inc., Perclose has provided each of the
holders of its common stock as of the close of business on August 16, 1999,
the record date, with a proxy statement/prospectus and a supplement dated
November 8, 1999 to the proxy statement/prospectus describing the merger.
Following the distribution of the proxy statement/prospectus and the
supplement to the proxy statement/prospectus, the board of directors of
Abbott has adopted a shareholder rights plan as described below.  This
supplement to the proxy statement/prospectus is being distributed for
informational and SEC disclosure purposes only.

ADOPTION OF SHAREHOLDER RIGHTS PLAN

     On November 10, 1999, the Abbott board of directors declared a dividend
distribution of one right for each outstanding share of Abbott common stock
to shareholders of record at the close of business on December 1, 1999, the
record date.  Except as described below, each right, when exercisable,
entitles the registered holder to purchase from Abbott one ten-thousandth of
a share of Abbott's series A junior participating preferred stock, par value
$1.00 per share, at a purchase price of $200.00 for each one ten-thousandth
of a share, subject to adjustment.  The description and terms of the rights
are set forth in a form of rights agreement which was filed with the
Securities and Exchange Commission as an exhibit to Abbott's Current Report
on Form 8-K dated November 10, 1999.

     Initially, the rights will automatically attach to all Abbott common
stock certificates representing shares then outstanding, and no separate
certificates evidencing the rights will be distributed.  The rights will be
evidenced by the common stock certificates and not by separate certificates
until the earlier to occur of:

     -    ten days following a public announcement that a person or group of
          affiliated or associated persons, referred to as the acquiring
          persons, has acquired, or obtained the right to acquire, beneficial
          ownership of 10% or more of Abbott's outstanding common stock, which
          is what the rights agreement calls the shares acquisition date; or

     -    15 business days, or a later date as may be determined by action of
          the Abbott board of directors prior to the time that any person
          becomes an acquiring person, following the commencement of, or a
          public announcement of an intention to make, a tender or exchange
          offer if, upon consummation of that offer, the acquiring person or
          persons  would be the beneficial owner of 10% or more of Abbott's
          outstanding common stock.

The earlier of these two dates is referred to in the rights agreement as the
distribution date.

     The rights agreement also provides that, until the distribution date,
the rights will be transferred with and only with the Abbott common stock.
Until the distribution date or earlier redemption, expiration or termination
of the rights, the transfer of any certificates for Abbott common stock will
also constitute the transfer of the rights associated with the Abbott common
stock represented by such certificates.  As soon as practicable following the
distribution date, right certificates will be mailed to holders of record of



the Abbott common stock as of the close of business on the distribution date,
and, subsequently, such separate right certificates alone will evidence the
rights. Any shares of Abbott common stock issued after the distribution date
will generally be accompanied by right certificates only if such shares of
Abbott common stock are issued pursuant to the exercise of options or under
any employee plan or arrangement or upon the exercise, conversion or exchange
of other securities issued by Abbott, or in other circumstances where the
issuance of accompanying right certificates is deemed necessary or
appropriate by the Abbott board of directors.

     The rights are not exercisable until the distribution date and will
expire at the earliest of:

     -    November 10, 2009, the final expiration date;

     -    upon redemption by Abbott as described below; or

     -    upon exchange of all rights for Abbott common stock as described
          below.

     If any person, other than Abbott, its affiliates or any person receiving
newly-issued shares of Abbott common stock directly from Abbott, becomes the
beneficial owner of 10% or more of the then outstanding shares of Abbott
common stock, each rightsholder will subsequently have the right to receive,
upon exercise at the then current exercise price of the right, Abbott common
stock, or, in certain circumstances, cash, property or other securities of
Abbott, having a value equal to two times the exercise price of the right.

     If, after an acquiring person obtains 10% or more of the outstanding
Abbott common stock, Abbott is acquired in a merger or other business
combination transaction or 50% or more of Abbott's assets or earning power
are sold, proper provision will be made so that each holder of a right will
subsequently have the right to receive, upon exercise at the then current
exercise price of the right, common stock of the acquiring or surviving
company having a value equal to two times the exercise price of the right.

     Notwithstanding the foregoing, following the occurrence of any of the
events set forth in the preceding two paragraphs, any rights that are, or,
under certain circumstances specified in the rights agreement, were,
beneficially owned by any acquiring person will immediately become null and
void.

     At any time after the acquisition by a person or group of affiliated or
associated persons of beneficial ownership of 10% or more of the outstanding
Abbott common stock and prior to the acquisition by that person or group of
50% or more of the outstanding Abbott common stock or the existence of a
solicitation participant, the Abbott board of directors may exchange the
rights, other than rights owned by that person or group, which have become
void, in whole or in part, at an exchange ratio of one share of Abbott common
stock for each right, subject to adjustment.

     Subject to the following paragraph, at any time after the date of the
rights agreement until the earlier of the time that a person becomes an
acquiring person or November 10, 2009, the Abbott board of directors may
redeem the rights in whole, but not in part, at a price of $.0001 for each
right, which may, at the option of Abbott, be paid in cash, shares of Abbott
common stock or other consideration deemed appropriate by the Abbott board of
directors.  Upon the effectiveness of any action of the Abbott board of


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directors ordering redemption of the rights, the rights will terminate
leaving the rightsholders with only the right to receive this redemption
price.

     If, at any time prior to a person becoming an acquiring person:

     -    there occurs a change, resulting from one or more proxy or consent
          solicitations, in a majority of the directors in office at the
          commencement of the first of these solicitations and

     -    any person who is a participant in any of these solicitations has
          proposed or initiated a business combination transaction involving
          Abbott,

then the approval by holders of at least 85% of the outstanding shares of
Abbott common stock, known as the shareholder approval, would be required
prior to any redemption of the rights or any amendment of the rights
agreement that would adversely affect the interests of rightsholders or
facilitate a transaction with a solicitation participant.

     The rights have certain anti-takeover effects.  The rights will cause
substantial dilution to a person or group that attempts to acquire Abbott
without conditioning the offer on the rights being redeemed or a substantial
number of rights being acquired, and under certain circumstances the rights
beneficially owned by that person or group may become void.  The rights
should not interfere with any merger or other business combination approved
by the Abbott board of directors because the Abbott board of directors may,
at its option and subject to shareholder approval, if applicable, at any time
prior to the time that any person becomes an acquiring person, redeem all,
but not less than all, of the then outstanding rights at the redemption price.

     This summary description of the rights does not purport to be complete
and is qualified in its entirety by reference to the rights agreement.


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