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This announcement is neither an offer to purchase nor a solicitation of an offer
to sell Shares (as defined below). The Offer (as defined below) is made solely
by the Offer to Purchase, dated October 19, 2000, and the related Letter of
Transmittal and any amendments or supplements thereto, and is being made to all
holders of Shares except for Parent and Purchaser (as defined below). The Offer
is not being made to (nor will tenders be accepted from or on behalf of) holders
of Shares in any jurisdiction in which the making of the Offer or the acceptance
thereof would not be in compliance with the laws of such jurisdiction. In any
jurisdiction where the securities, blue sky or other laws require the Offer to
be made by a licensed broker or dealer, the Offer will be deemed to be made on
behalf of Purchaser by Lehman Brothers, Inc. as Dealer Manager (as defined
below) and by one or more registered brokers or dealers that are licensed under
the laws of such jurisdiction.

Notice of Offer to Purchase for Cash
All Outstanding Shares of Class A Common Stock
and Class B Common Stock
of
Block Drug Company, Inc.
at
$53.00 Net Per Share
by
SB Acquisition Corp.
a wholly-owned subsidiary of
SmithKline Beecham plc

SB Acquisition Corp., a New Jersey corporation ("Purchaser") and a wholly-owned
subsidiary of SmithKline Beecham plc, a public limited company organized under
the laws of the England and Wales ("Parent"), is offering to purchase all
outstanding shares of Class A common stock, par value $.10 per share, and,
separately, all outstanding shares of Class B common stock, par value $.10 per
share (the "Class A Stock" and "Class B Stock," respectively, and collectively,
the "Shares"), of Block Drug Company, Inc., a New Jersey corporation (the
"Company") which are not owned by Parent, Purchaser or their respective
affiliates, in the case of each offer at $53.00 per share, net to the seller in
cash (the "Share Price"), without interest. Such offers are being made together
upon the terms and subject to the conditions set forth in the Offer to Purchase,
dated October 19, 2000, and in the related Letter of Transmittal, together with
any amendments or supplements thereto. (As used herein the term "Offer" refers
to each such offer separately and where the context requires, to the offers,
collectively.) Tendering shareholders will not be obligated to pay brokerage
fees or commissions or, except as set forth in Instruction 6 of the Letter of
Transmittal, transfer taxes on the purchase of Shares by Purchaser pursuant to
the Offer. The purpose of the Offer is to acquire for cash as many outstanding
Shares as possible as a first step in acquiring the entire equity interest in
the Company. Following the consummation of the Offer, Purchaser intends to
effect the Merger (as defined below).

THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT, NEW YORK CITY
TIME, ON December 13, 2000, UNLESS THE OFFER IS EXTENDED.

The Offer is conditioned upon, among other things, (i) there having been validly
tendered and

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not properly withdrawn prior to the expiration of the Offer that number of
Shares which, together with any Shares then beneficially owned by Purchaser or
Parent or any of their respective affiliates, represents (A) 100% of the Class B
Stock and (B) at least a majority of the total number of outstanding shares of
Class A Stock and Class B Stock (taken together as if a single class), in each
case on a fully diluted basis (the "Minimum Tender Condition"), (ii) the
expiration or termination prior to the Expiration Date of any waiting period
under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended,
applicable to the purchase of Shares pursuant to the Offer, and (iii) the
receipt of any required approval under Regulation 4064/899/EC concerning the
control of concentrations between undertakings adopted by the Council of
European Communities on December 21, 1989, as amended; in each case as described
in further detail in the Offer to Purchase. Certain other conditions to the
Offer are described in Section 13 of the Offer to Purchase.

The Offer is being made pursuant to an Agreement and Plan of Merger (the "Merger
Agreement"), dated as of October 7, 2000, among the Company, Parent and
Purchaser, pursuant to which, after completion of the Offer and the satisfaction
or waiver of certain conditions, Purchaser will be merged with and into the
Company and the Company will be the surviving corporation (the "Merger") and
each issued and outstanding Share (other than Shares owned by Parent, Purchaser
or any subsidiary or affiliate of Parent, Purchaser or the Company or held in
the treasury of the Company) will, by virtue of the Merger and without any
action on the part of the holder thereof, be canceled and converted into the
right to receive an amount in cash, without interest, equal to the Share Price
paid pursuant to the Offer. The Merger Agreement is more fully described in the
Offer to Purchase.

Parent and Purchaser have also entered into a Voting and Tender Agreement dated
as of October 7, 2000 with certain shareholders of the Company who own an
aggregate of approximately 52% of the outstanding shares of Class A Stock and
100% of the outstanding shares of Class B Stock. Under the terms of the Voting
and Tender Agreement those shareholders have agreed to tender their Shares into
the Offer and to vote in favor of the Merger.

The Board of Directors of the Company has unanimously approved (with one
director absent) the Merger Agreement, approved the Offer and the Merger,
determined that the Offer and the Merger are advisable and fair to, and in the
best interests of, the holders of Shares (other than Parent and its affiliates)
and recommends that shareholders accept the Offer and tender their Shares
pursuant to the Offer.

For purposes of the Offer, Purchaser will be deemed to have accepted for
payment, and thereby purchased, Shares validly tendered and not properly
withdrawn if and when Purchaser gives oral or written notice to HSBC Bank USA
(the "Depositary") of its acceptance for payment of such Shares pursuant to the
Offer. Upon the terms and subject to the conditions of the Offer, payment for
Shares accepted for payment pursuant to the Offer will be made by deposit of the
purchase price therefor with the Depositary, which will act as agent for the
tendering shareholders for the purpose of receiving payments from Purchaser and
transmitting such payments to the tendering shareholders. Under no circumstances
will interest be paid on the purchase price for Shares, regardless of any
extension of the Offer or any delay in making such payment. In all cases,
payment for Shares tendered and accepted for payment pursuant to the Offer will
be made only after timely receipt by the Depositary of (a) certificates for such
Shares or confirmation of the book-entry transfer of such Shares

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into the Depositary's account at The Depository Trust Company (the "Book-Entry
Transfer Facility") pursuant to the procedures set forth in Section 3 of the
Offer to Purchase, (b) a Letter of Transmittal (or facsimile thereof), properly
completed and duly executed, with any required signature guarantees (or, in the
case of a book-entry transfer, an Agent's Message (as defined in Section 3 of
the Offer to Purchase) in lieu of the Letter of Transmittal) and (c) any other
documents required by the Letter of Transmittal.

Tenders of Shares made pursuant to the Offer are irrevocable, except that Shares
tendered pursuant to the Offer may be withdrawn at any time prior to the
Expiration Date and, unless theretofore accepted for payment by Purchaser
pursuant to the Offer, may also be withdrawn at any time after December 18,
2000, except as provided with respect to any subsequent offering period. The
term "Expiration Date" means 12:00 midnight, New York City time, on December 13,
2000, unless Purchaser, in its sole discretion (subject to the terms of the
Merger Agreement), shall have extended the period of time during which the Offer
is open, in which event the term "Expiration Date" shall mean the latest time
and date on which the Offer, as so extended by Purchaser, shall expire. Subject
to the terms of the Merger Agreement and the applicable rules and regulations of
the Securities and Exchange Commission, Purchaser expressly reserves the right
(but will not be obligated), in its sole discretion, at any time or from time to
time, to extend the period of time during which the Offer is open by giving oral
or written notice of such extension to the Depositary. Any such extension will
be followed as promptly as practicable by public announcement thereof, such
announcement to be issued no later than 9:00 a.m., New York City time, on the
next business day after the previously scheduled Expiration Date. During any
such extension, all Shares previously tendered and not withdrawn will remain
subject to the Offer, subject to the right of a tendering shareholder to
withdraw such shareholder's Shares.

For a withdrawal to be effective, a written or facsimile transmission notice of
withdrawal must be timely received by the Depositary at its address set forth on
the back cover of the Offer to Purchase. Any such notice of withdrawal must
specify the name of the person having tendered the Shares to be withdrawn, the
number of Shares to be withdrawn and the name of the recordholder of the Shares
to be withdrawn, if different from that of the person who tendered such Shares.
The signature(s) on the notice of withdrawal must be guaranteed by an Eligible
Institution (as defined in Section 3 of the Offer to Purchase), unless such
Shares have been tendered for the account of any Eligible Institution. If Shares
have been tendered pursuant to the procedures for book-entry transfer as set
forth in Section 3 of the Offer to Purchase, any notice of withdrawal must
specify the name and number of the account at the Book-Entry Transfer Facility
to be credited with the withdrawn Shares and otherwise comply with the
Book-Entry Transfer Facility's procedures. If certificates for Shares to be
withdrawn have been delivered or otherwise identified to the Depositary, the
name of the registered holder and the serial numbers shown on such certificates
must also be furnished to the Depositary as aforesaid prior to the physical
release of such certificates. All questions as to the form and validity
(including time of receipt) of any notice of withdrawal will be determined by
Purchaser, in its sole discretion, which determination shall be final and
binding. None of Parent, Purchaser, the Depositary, the Information Agent
(listed below), or any other person will be under any duty to give notification
of any defects or irregularities in any notice of withdrawal or incur any
liability for failure to give such notification. Withdrawals of tenders of
Shares may not be rescinded, and any Shares properly withdrawn will be deemed
not to have

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been validly tendered for purposes of the Offer. However, withdrawn Shares may
be retendered by following one of the procedures described in Section 3 of the
Offer to Purchase at any time prior to the Expiration Date.


Under the Merger Agreement and pursuant to Rule 14d-11 of the General Rules and
Regulations under the Securities Exchange Act of 1934, as amended (the "Exchange
Act"), Purchaser may, subject to certain conditions, include a subsequent
offering period following the Expiration Date. Purchaser does not currently
intend to include a subsequent offering period in the Offer, although it
reserves the right to do so in its sole discretion. In the event Purchaser
provides a subsequent offering period, withdrawal rights will not apply to
Shares tendered during such subsequent offering period and withdrawal rights
will not apply during such subsequent offering period with respect to Shares
tendered in the Offer and accepted for payment. See Section 1 of the Offer to
Purchase.

The information required to be disclosed by paragraph (d)(1) of Rule 14d-6 of
the General Rules and Regulations under the Exchange Act is contained in the
Offer to Purchase and is incorporated herein by reference.

The Company has provided Purchaser with the Company's list of shareholders and
security position listings for the purpose of disseminating the Offer to holders
of Shares. The Offer to Purchase and the Letter of Transmittal will be mailed by
Purchaser to recordholders of Shares whose names appear on the Company's
shareholders list and will be furnished to brokers, dealers, commercial banks,
trust companies and similar persons whose names, or the names of whose nominees,
appear on the shareholder list or, if applicable, who are listed as participants
in a clearing agency's security position listing for subsequent transmittal to
beneficial owners of Shares.

The Offer to Purchase and the related Letter of Transmittal contain important
information which should be read carefully before any decision is made with
respect to the Offer. Questions and requests for assistance may be directed to
the Information Agent at the address and telephone number set forth below.
Requests for additional copies of the Offer to Purchase and the related Letter
of Transmittal may be directed to the Information Agent or to brokers, dealers,
commercial banks or trust companies. Such additional copies will be furnished at
Purchaser's expense. Purchaser, the Dealer Manager and the Depositary will not
pay any fees or commissions to any broker or dealer or any other person (other
than the Information Agent) for soliciting tenders of Shares pursuant to the
Offer.

The Information Agent for the Offer is:

Morrow & Co., Inc.
445 Park Avenue, 5th Floor
New York, NY 10022
E-mail: information@morrowco.com
Call Collect: (212) 754-8000
Banks and Brokerage Firms, Please Call: (800) 662-5200
Shareholders Please Call: (800) 566-9061

The Dealer Manager for the Offer is:
LEHMAN BROTHERS
Three World Financial Center
200 Vesey Street
New York, New York 10285
Call Collect: (212) 526-3968 or (212) 526-5661
October 19, 2000


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