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                                                                    Exhibit 10.1

                              BIOSITE INCORPORATED

                AMENDED AND RESTATED EMPLOYEE STOCK PURCHASE PLAN




         SECTION 1.  PURPOSE OF THE PLAN.

         The Plan was adopted by the Company's Board of Directors on December 5,
1996. On February 27, 1998, and January 19, 2001 the Plan was amended to
increase the number of shares available under the Plan. The purpose of the Plan
is to provide Eligible Employees with an opportunity to increase their
proprietary interest in the success of the Company by purchasing Stock from the
Company on favorable terms and to pay for such purchases through payroll
deductions. The Plan is intended to qualify under section 423 of the Internal
Revenue Code of 1986, as amended.

         SECTION 2.  ADMINISTRATION OF THE PLAN.

         (a) THE COMMITTEE. The Plan shall be administered by the Committee. The
interpretation and construction by the Committee of any provision of the Plan or
of any right to purchase Stock granted under the Plan shall be conclusive and
binding on all persons.

         (b) RULES AND FORMS. The Committee may adopt such rules and forms under
the Plan as it considers appropriate.

         SECTION 3.  ENROLLMENT AND PARTICIPATION.

         (a) OFFERING PERIODS. While the Plan is in effect, two overlapping
Offering Periods shall commence in each calendar year. Except for the first
Offering Period, Offering Periods shall consist of the 24-month periods
commencing on each January 1 and July 1. The first Offering Period shall
commence on the effective date of the Company's initial public offering and end
on December 31, 1996.

         (b) ACCUMULATION PERIODS. While the Plan is in effect, two Accumulation
Periods shall commence in each calendar year. Except for the first Accumulation
Period, Accumulation Periods shall consist of the six-month periods commencing
on each January 1 and July 1. The first Accumulation Period shall commence on
the effective date of the Company's initial public offering and end on June 30,
1997.

         (c) ENROLLMENT. Any individual who, on the day preceding the first day
of an Offering Period, qualifies as an Eligible Employee may elect to become a
Participant in the Plan for such Offering Period by executing the enrollment
form prescribed for this purpose by the Committee. The enrollment form shall be
filed with the Company not late than one week prior to the last working day
prior to the commencement of such Offering Period.



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         (d) DURATION OF PARTICIPATION. Once enrolled in the Plan, a Participant
shall continue to participate until he or she ceases to be an Eligible Employee,
withdraws from the Plan or reaches the end of the Accumulation Period in which
he or she discontinued contributions. A Participant who discontinued
contributions under Section 4(d) or withdrew from the Plan under Section 5(a)
may again become a Participant, if he or she then is an Eligible Employee, by
following the procedure described in Subsection (c) above.

         (e) APPLICABLE OFFERING PERIOD. For the purposes of calculating the
Purchase Price under Section 7(b), the applicable Offering Period shall be
determined as follows:

                  (i) Once a Participant is enrolled in the Plan for an Offering
         Period, such Offering Period shall continue to apply to him or her
         until the earliest of (A) the end of such Offering Period, (B) the end
         of his or her participation under Subsection (d) above or (C)
         reenrollment in a subsequent Offering Period under Paragraph (ii)
         below.

                  (ii) In the event that the Fair Market Value of Stock on the
         last trading day before the commencement of the Offering Period in
         which the Participant is enrolled is higher than on the last trading
         day before the commencement of any subsequent Offering Period, the
         Participant shall automatically be re-enrolled for such subsequent
         Offering Period.

                  (iii) When a Participant reaches the end of an Offering Period
         but his or her participation is to continue, then such Participant
         shall automatically be re-enrolled for the Offering Period that
         commences immediately after the end of the prior Offering Period.

         SECTION 4.  EMPLOYEE CONTRIBUTIONS.

         (a) FREQUENCY OF PAYROLL DEDUCTIONS. A Participant may purchase shares
of Stock under the Plan solely by means of payroll deductions. Payroll
deductions, as designated by the Participant pursuant to Subsection (b) below,
shall occur on each payday during participation in the Plan.

         (b) AMOUNT OF PAYROLL DEDUCTIONS. An Eligible Employee shall designate
on the enrollment form the portion of his or her Compensation that he or she
elects to have withheld for the purchase of Stock. Such portion shall be a whole
percentage of the Eligible Employee's Compensation, but not less than 1% percent
nor more than 15%.

         (c) CHANGING WITHHOLDING RATE. If a Participant wishes to change the
rate of payroll withholding, he or she may do so by filing a new enrollment form
with the Company not later than one week prior to the last working day prior to
the commencement of the Accumulation Period for which such change is to be
effective.

         (d) DISCONTINUING PAYROLL DEDUCTIONS. If a Participant wishes to
discontinue employee contributions entirely, he or she may do so by filing a new
enrollment form at any time. Payroll withholding shall cease as soon as
reasonably practicable after such form has been received by the Company.

         SECTION 5.  WITHDRAWAL FROM THE PLAN.

         (a) WITHDRAWAL. A Participant may elect to withdraw from the Plan by
filing the prescribed form with the Company at any time before the last day of
an Accumulation Period. As soon as reasonably practicable thereafter, payroll
deductions shall cease and the entire amount credited to the Participant's Plan
Account shall be refunded to him or her in cash, without interest. No partial
withdrawals shall be permitted.

         (b) RE-ENROLLMENT AFTER WITHDRAWAL. A former Participant who has
withdrawn from the Plan shall not be a Participant until he or she re-enrolls in
the Plan under Section 3(b).

         SECTION 6.  CHANGE IN EMPLOYMENT STATUS.


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         (a) TERMINATION OF EMPLOYMENT. Termination of employment as an Eligible
Employee for any reason, including death, shall be treated as an automatic
withdrawal from the Plan under Section 5(a). (A transfer from one Participating
Company to another shall not be treated as a termination of employment.)

         (b) DEATH. In the event of the Participant's death, the amount credited
to his or her Plan Account shall be paid to a beneficiary designated by him or
her for this purpose on the prescribed form or, if none, to the Participant's
estate. Such form shall be valid only if it was filed with the Company before
the Participant's death.

         SECTION 7.  PLAN ACCOUNTS AND PURCHASE OF SHARES.

         (a) PLAN ACCOUNTS. The Company shall maintain a Plan Account on its
books in the name of each Participant. Whenever an amount is deducted from the
Participant's Compensation under the Plan, such amount shall be credited to the
Participant's Plan Account. No interest shall be credited to Plan Accounts.

         (b) PURCHASE PRICE. The Purchase Price for each share of Stock
purchased at the close of an Accumulation Period shall be the lower of:

                  (i) 85% of the Fair Market Value of such share on the last
         trading day before the commencement of the applicable Offering Period
         (as determined under Section 3(e); or

                  (ii) 85% of the Fair Market Value of such share on the last
         trading day in such Accumulation Period.

         (c) NUMBER OF SHARES PURCHASED. As of the last day of each Accumulation
Period, each Participant shall be deemed to have elected to purchase the number
of shares of Stock calculated in accordance with this Subsection (c), unless the
Participant has previously elected to withdraw from the Plan in accordance with
Section 5(a). The amount then in the Participant's Plan Account shall be divided
by the Purchase Price, and the number of shares that results shall be purchased
from the Company with the funds in the Participant's Plan Account. The foregoing
notwithstanding, no Participant shall purchase more than a maximum of 2,500
shares of Stock with respect to any Accumulation Period nor shares of Stock in
excess of the amounts set forth in Sections 8 and 12(a). The Committee may
determine with respect to all Participants that any fractional share, as
calculated under this Subsection (c), shall be rounded down to the next lower
whole share.

         (d) AVAILABLE SHARES INSUFFICIENT. In the event that as of the
beginning of an Accumulation Period the Committee determines that the aggregate
number of shares that all Participants are projected or are likely to elect
during an Accumulation Period exceeds the maximum number of shares remaining
available for issuance under Section 12(a), including in connection with an
Offering Period beginning prior to the date of the Accumulation Period with
insufficient shares, then the Committee may either determine that such shares
shall not be made in connection with any previous Offering Period but shall be
added to any new increase in the shares available under the Plan in a new
Offering Period starting on the date of the Accumulation Period with
insufficient shares, or the number of shares to which each Participant is
entitled in any Offering Period shall be determined by multiplying the number of
Shares available for issuance by a fraction, the numerator of which is the
number of shares that such Participant has elected to purchase and the
denominator of which is the number of shares that all Participants have elected
to purchase. In the event the Committee does not make any determination, the
default method for dealing with insufficient shares in an Accumulation Period
shall be the fractional method described in the preceding sentence.

         (e) ISSUANCE OF STOCK. Certificates representing the number of shares
of Stock purchased by a Participant under the Plan shall be issued to him or her
as soon as reasonably practicable after the close of the applicable Accumulation
Period, except that the Committee may determine that such shares shall be held
for each Participant's benefit by a broker designated by the Committee (unless
the Participant has elected that certificates be issued to him or her). Shares
may be registered in the name of the Participant or jointly in the name of the
Participant and his or her spouse as joint tenants with right of survivorship or
as community property.

         (f) UNUSED CASH BALANCES. An amount remaining in the Participant's Plan
Account that represents the Purchase Price for any fractional share shall be
carried over in the Participant's Plan Account to the next Accumulation Period.
Any amount remaining in the Participant's Plan Account that represents the
Purchase Price for whole shares that


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could not be purchased by reason of Subsection (c) above, Section 8 or Section
12(a) shall be refunded to the Participant in cash, without interest.

         (g) FAILURE OF STOCKHOLDERS TO APPROVE PLAN. In the event stockholders
of the Company do not approve this Plan, the Participant's Plan Account shall be
repaid to the Participant in cash and no Company shares will be purchased for
the Participant under this Plan.

         SECTION 8.  LIMITATIONS ON STOCK OWNERSHIP.

         Any other provision of the Plan notwithstanding, no Participant shall
be granted a right to purchase Stock under the Plan if:

         (a) Such Participant, immediately after his or her election to purchase
such Stock, would own stock possessing more than 5% of the total combined voting
power or value of all classes of stock of the Company or any Parent or
Subsidiary of the Company; or

         (b) Under the terms of the Plan, such Participant's rights to purchase
stock under this and all other qualified employee stock purchase plans of the
Company or any Parent or Subsidiary of the Company would accrue at a rate that
exceeds $25,000 of the fair market value of such stock (determined at the time
when such right is granted) for each calendar year for which such right or
option is outstanding at any time.

         Ownership of stock shall be determined after applying the attribution
rules of section 424(d) of the Internal Revenue Code of 1986, as amended. For
purposes of this Section 8, each Participant shall be considered to own any
stock that he or she has a right or option to purchase under this or any other
plan, and each Participant shall be considered to have the right to purchase
2,500 shares of Stock under this Plan with respect to each Accumulation Period.

         SECTION 9.  RIGHTS NOT TRANSFERABLE.

         The rights of any Participant under the Plan, or any Participant's
interest in any Stock or moneys to which he or she may be entitled under the
Plan, shall not be transferable by voluntary or involuntary assignment or by
operation of law, or in any other manner other than by beneficiary designation
or the laws of descent and distribution. If a Participant in any manner attempts
to transfer, assign or otherwise encumber his or her rights or interest under
the Plan, other than by beneficiary designation or the laws of descent and
distribution, then such act shall be treated as an election by the Participant
to withdraw from the Plan under Section 5(a).

         SECTION 10.  NO RIGHTS AS AN EMPLOYEE.

         Nothing in the Plan shall be construed to give any person the right to
remain in the employ of a Participating Company. Each Participating Company
reserves the right to terminate the employment of any person at any time, with
or without cause.

         SECTION 11.  NO RIGHTS AS A STOCKHOLDER.

         A Participant shall have no rights as a stockholder with respect to any
shares that he or she has purchased, or may have a right to purchase, under the
Plan until the date of issuance of a stock certificate for such shares.

         SECTION 12.  STOCK OFFERED UNDER THE PLAN.

         (a) AUTHORIZED SHARES. The aggregate number of shares of Stock
available for purchase under the Plan shall be 550,000, subject to adjustment
pursuant to this Section 12.

         (b) ANTI-DILUTION ADJUSTMENTS. The aggregate number of shares of Stock
offered under the Plan, the 2,500-share limitation described in Section 7(c) and
the price of shares that any Participant has elected to purchase shall be
adjusted proportionately by the Committee for any increase or decrease in the
number of outstanding shares of Stock



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resulting from a subdivision or consolidation of shares, the payment of a stock
dividend, any other increase or decrease in such shares effected without receipt
or payment of consideration by the Company, or the distribution of the shares of
a Subsidiary to the Company's stockholders.

         (c) REORGANIZATIONS. In the event of a dissolution or liquidation of
the Company, or a merger or consolidation to which the Company is a constituent
corporation, the Plan shall terminate unless the plan of merger, consolidation
or reorganization provides otherwise, and all amounts that have been withheld
but not yet applied to purchase Stock hereunder shall be refunded, without
interest. The Plan shall in no event be construed to restrict in any way the
Company's right to undertake a dissolution, liquidation, merger, consolidation
or other reorganization.

         SECTION 13.  AMENDMENT OR DISCONTINUANCE.

         The Board of Directors shall have the right to amend, suspend or
terminate the Plan at any time and without notice. Except as provided in Section
12, any increase in the aggregate number of shares of Stock to be issued under
the Plan shall be subject to approval by a vote of the stockholders of the
Company. In addition, any other amendment of the Plan shall be subject to
approval by a vote of the stockholders of the Company to the extent required by
an applicable law or regulation.

         SECTION 14.  DEFINITIONS.

         (a) "ACCUMULATION PERIOD" means a six-month period during which
contributions may be made toward the purchase of Stock under the Plan, as
determined pursuant to Section 3(b).

         (b) "BOARD OF DIRECTORS" means the Board of Directors of the Company,
as constituted from time to time.

         (c) "COMMITTEE" means a committee of the Board of Directors, consisting
of one or more directors appointed by the Board of Directors.

         (d) "COMPANY" means Biosite Diagnostics Incorporated, a Delaware
corporation.

         (e) "COMPENSATION" means the total compensation paid in cash to a
Participant by a Participating Company, including salaries, wages, overtime pay
and commissions, but excluding bonuses, incentive compensation, moving or
relocation allowances, car allowances, imputed income attributable to cars or
life insurance, taxable fringe benefits and similar items, all as determined by
the Committee.

         (f)  "ELIGIBLE EMPLOYEE" means any employee of a Participating Company:

                  (i) Whose customary employment is for more than five months
         per calendar year and for more than 20 hours per week; and

                  (ii) Who has been an employee of a Participating Company for
         not less than one month.

         (g) "FAIR MARKET VALUE" shall mean the market price of Stock,
determined by the Committee as follows:

                  (i) If the Stock was traded over-the-counter on the date in
         question but was not traded on the Nasdaq Stock Market or the Nasdaq
         National Market, then the Fair Market Value shall be equal to the mean
         between the last reported representative bid and asked prices quoted
         for such date by the principal automated inter-dealer quotation system
         on which Stock is quoted or, if the Stock is not quoted on any such
         system, by the "Pink Sheets" published by the National Quotation
         Bureau, Inc.;

                  (ii) If the Stock was traded over-the-counter on the date in
         question and was traded on the Nasdaq Stock Market or the Nasdaq
         National Market, then the Fair Market Value shall be equal to the
         last-transaction price quoted for such date by the Nasdaq Stock Market
         or the Nasdaq National Market;


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                  (iii) If the Stock was traded on a stock exchange on the date
         in question, then the Fair Market Value shall be equal to the closing
         price reported by the applicable composite transactions report for such
         date; and

                  (iv) If none of the foregoing provisions is applicable, then
         the Fair Market Value shall be determined by the Committee in good
         faith on such basis as it deems appropriate.

Whenever possible, the determination of Fair Market Value by the Committee shall
be based on the prices reported in the Western Edition of THE WALL STREET
JOURNAL or as reported directly to the Company by Nasdaq or a comparable
exchange. Such determination shall be conclusive and binding on all persons.

         (h) "OFFERING PERIOD" means a 24-month period with respect to which the
right to purchase Stock my be granted under the Plan, as determined pursuant to
Section 3(a).

         (i) "PARTICIPANT" means an Eligible Employee who elects to participate
in the Plan, as provided in Section 3(c).

         (j) "PARTICIPATING COMPANY" means the Company and each present or
future Subsidiary, except Subsidiaries excluded by the Committee.

         (k) "PLAN" means this Biosite Diagnostics Incorporated Employee Stock
Purchase, as amended from time to time.

         (l) "PLAN ACCOUNT" means the account established for each Participant
pursuant to Section 6(a).

         (m) "PURCHASE PRICE" means the price at which Participants may purchase
Stock under the Plan, as determined pursuant to Section 7(b).

         (n)  "STOCK" means the Common Stock of the Company.

         (o) "SUBSIDIARY" means a corporation, 50% or more of the total combined
voting power of all classes of stock of which is owned by the Company or by
another Subsidiary.

         SECTION 15.  EXECUTION.

         To record the adoption of the Plan by the Board of Directors, the
Company has caused its duly authorized officer to affix the corporate name and
seal hereto.


                                       BIOSITE INCORPORATED



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