[FACE OF
CERTIFICATE]

NUMBER

U

SEE
REVERSE FOR CERTAIN DEFINITIONS

HEALTHCARE
ACQUISITION CORP.

UNITS
CONSISTING OF ONE SHARE OF COMMON STOCK AND ONE WARRANT TO PURCHASE ONE SHARE OF
COMMON STOCK

U N I T
S

CUSIP TO
COME

This
Certifies that

is the
owner of ____________ Units.




Each Unit
(“Unit”) consists of one (1) share of common stock, par value $.0001 per share
(“Common Stock”), of Healthcare Acquisition Corp., a Delaware corporation (the
“Company”), and one warrant (the “Warrant”). Each Warrant entitles the holder to
purchase one (1) share of Common Stock for $6.00 per share (subject to
adjustment). Each Warrant will become exercisable on the later of (i) the
Company’s completion of a merger, capital stock exchange, asset acquisition or
other similar business combination and (ii) , 2006, and will expire unless
exercised before 5:00 p.m., New York City Time, on , 2009, or earlier upon
redemption (the “Expiration Date”). The Common Stock and Warrants comprising the
Units represented by this certificate are not transferable separately prior to ,
2005, subject to earlier separation in the discretion of Maxim Group LLC. The
terms of the Warrants are governed by a Warrant Agreement, dated as of , 2005,
between the Company and Continental Stock Transfer & Trust Company, as
Warrant Agent, and are subject to the terms and provisions contained therein,
all of which terms and provisions the holder of this certificate consents to by
acceptance hereof. Copies of the Warrant Agreement are on file at the office of
the Warrant Agent at 17 Battery Place, New York, New York 10004, and are
available to any Warrant holder on written request and without
cost.




This
certificate is not valid unless countersigned by the Transfer Agent and
Registrar of the Company.

Witness
the facsimile seal of the Company and the facsimile signature of its duly
authorized officers.




By

SECRETARY

[SEAL]

PRESIDENT

COUNTERSIGNED
AND REGISTERED:

CONTINENTAL
STOCK TRANSFER & TRUST COMPANY

TRANSFER
AGENT AND REGISTRAR

BY

AUTHORIZED
SIGNATURE























[REVERSE
OF CERTIFICATE]

Healthcare
Acquisition Corp.

The
Company will furnish without charge to each stockholder who so requests, a
statement of the powers, designations, preferences and relative, participating,
optional or other special rights of each class of stock or series thereof of the
Company and the qualifications, limitations, or restrictions of such preferences
and/or rights.




The
following abbreviations, when used in the inscription on the face of this
certificate, shall be construed as though they were written out in full
according to applicable laws or regulations:

TEN COM -
as tenants in common

TEN ENT -
as tenants by the entireties

JT TEN -
as joint tenants with right of survivorship and not as tenants in
common

UNIF GIFT
MIN ACT- (Cust) Custodian (Minor) under Uniform Gifts to Minors Act
(State)

Additional
abbreviations may also be used though not in the above list.

For value
received, ___________________________ hereby sell, assign and transfer
unto

PLEASE
INSERT SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER OF ASSIGNEE

(PLEASE
PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING ZIP CODE, OF
ASSIGNEE)

Units
represented by the within Certificate, and do hereby irrevocably constitute and
appoint ____________ 

Attorney
to transfer the said Units on the books of the within named Company with full
power of substitution in the premises.




Dated

Notice:
The signature to this assignment must correspond with the name as written upon
the face of the certificate in every particular, without alteration or
enlargement or any change whatever.




Signature(s)
Guaranteed:




THE
SIGNATURE(S) MUST BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION (BANKS,
STOCKBROKERS, SAVINGS AND LOAN ASSOCIATIONS AND CREDIT UNIONS WITH MEMBERSHIP IN
AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM, PURSUANT TO S.E.C. RULE
17Ad-15).