ASSET VALUE FUND LIMITED PARTNERSHIP
                          376 MAIN STREET, P.O. BOX 74
                              BEDMINSTER, NJ 07921
                                 (908) 234-1881


                                                             March __, 1998

Dear Fellow Cortech Stockholder:

     We and two other  investors  ("Asset Value") own  approximately  15% of the
outstanding shares of Cortech, Inc. ("Cortech"), which makes us by far Cortech's
largest stockholder.  At the upcoming Special Meeting,  Cortech proposes,  among
other things,  to merge with BioStar,  Inc.  ("BioStar"),  a company  located in
Boulder,  Colorado, which is losing money and has an accumulated deficit of more
than ($25,000,000) (the "Merger"). We oppose the Merger because in our view:
 
     (1) the terms of the Merger do not maximize Cortech's value and in fact the
terms are unfair to Cortech's public stockholders, and

     (2) the Cortech Board misstates that liquidation is the only alternative to
the Merger  when in fact if the poison pill were not in place,  we believe  that
Cortech  would have had and still could have numerous  suitors  better placed to
use Cortech's cash and tax operating loss carryforwards ("NOLs").

     We have read  carefully  the Joint Proxy  Statement/Prospectus  provided by
Cortech and BioStar,  including the so called fairness  opinion of its financial
adviser,  Cowen & Company ("Cowen").  We ask the Cortech Board:


           "PLEASE DISCLOSE WHAT YOU SEE IN THE HISTORY AND FINANCIAL
          STATEMENTS OF BIOSTAR THAT CHANGES FROM WHAT IS (IN OUR VIEW)
                     AN UGLY DUCKLING INTO A BEAUTIFUL SWAN"


     Kenneth  Lynn,  CEO of  Cortech  and his  hand-picked  Board  would have us
believe that once they  determined  in April 1997 that Cortech could not succeed
as a stand-alone entity, they scoured the land for a merger partner and the only
prospective  suitor was BioStar,  a company  which lost almost  ($2,000,000)  in
fiscal  1997 and by the end of 1997 had a  negative  net worth of  ($5,600,000).
BioStar is so poor that without Cortech or another cash source,  it has only six
months to live.  At its fiscal  year-end,  BioStar  lost $1,281 and had negative
working capital of ($3,100,000). According to Cowen, BioStar's earning prospects
are so scant that we believe one of Cortech's  principal  assets,  approximately
$77.2  million in NOLs,  are of little  value to BioStar  because it has its own
significant  NOLs.  The result,  in our view, is a Merger that does not maximize
Cortech's stockholder value. So what is it about BioStar that impressed Mr. Lynn
sufficiently   to  merge  it  with  Cortech  when,  in  our  view,  the  Cortech
stockholders do not gain from the Merger?


                                     WARNING

     In our  opinion,  several  individuals  and  entities,  other than  Cortech
stockholders,  reap the benefits of the Merger.  We believe that Mr. Lynn stands
to benefit from the Merger because it triggers his golden parachute  ($1,300,000
for him and his  management  team) and enables him (and other Board  members and
executive  officers) to exercise 623,535 options.  Cortech's regular



attorneys, Cooley  Goodward LLP,  stand to gain,  in our view,  because they are
representing  BioStar  in the  Merger and will  remain  counsel to the  combined
entity. Cowen,  Cortech's purportedly  independent advisor, will benefit because
its fee of  $250,000  soars to  $400,000,  an  increase of 60%, if the Merger is
consummated.  BioStar's management receives additional  compensation and options
in connection with the Merger and BioStar's Board receives  favorable  treatment
in the vesting and  exercise of its options.  In fact,  it seems to Asset Value,
that  every   participant   will  profit  from  the  Merger  except  the  public
stockholders  of Cortech  who will  suffer a dilution  in book value per Cortech
share  of 64%  (from an  historical  $.83 to a pro  forma  $.30)  while  BioStar
stockholders will enjoy an improvement in book value from an historical negative
($2.86) to a positive $.17.


       WOULD THE GODS GIVE US THE GIFT TO SEE OURSELVES AS OTHERS SEE US(1)
       -----------------------------------------------------------------
 
     Lynn has described  himself in this transaction as a "fiduciary".  Far from
it in our view.  Prior to the merger,  Lynn owned Cortech Shares worth less than
$2,000 in the  marketplace.  As a result of the Merger,  Lynn and his management
team will  receive:  (1)  payments of  $1,300,000;  (2) payment of premiums  for
health benefits for eighteen  months;  and (3) the immediate  vesting of 623,535
options. Mr. Lynn will also continue as a director of the successor  corporation
after the Merger.

     We believe that Mr. Lynn  negotiated  the terms of the Merger with apparent
disregard for stockholders' interests much like, in our view, he has ignored the
growing  disparity  over the past several  years  between his  interests and the
public stockholders'  interests. The chart below reflects the difference between
Mr. Lynn's  increasing  compensation  between 1993 and 1997 and the  concomitant
decline of the market value of Cortech Shares.





                 GRAPH OF CORTECH'S HIGH STOCK PRICE AND LYNN'S
                                  COMPENSATION.

                                       1993        1994       1995       1996        1997
                                      ------      ------     ------     ------      ------
                                                                     
Cortech's High Stock Price            $18.25      $14.25     $3.65625    $3.8125    $2.03125 
Lynn's Compensation                   $140,000    $181,744   $305,499    $330,006   $330,513




                                   NOT A PRETTY PICTURE!

- ------------------

     (1) An  anglicized  version  of a  quotation  from the poem "To a Louse" by
Scottish poet Robert Burns.




     When Asset Value  acquired its interest in Cortech in  September  1997,  we
asked the Cortech Board to elect a nominee of Asset Value to the Board (only one
on a five  member  Board).  The  Cortech  Board,  in effect,  refused,  then the
Directors  approved a transaction which, in our view, will negatively affect all
stockholders.  They did  this  without  bothering  to ask for,  or  permit,  the
participation of Cortech's largest  stockholder,  Asset Value,  whose interests,
clearly, in our opinion,  are more matched with public stockholders than a Board
which collectively owns less than 2-1/2 % of Cortech Shares.

           "WHO CARES WHAT OWNERS THINK? Who owns American companies?
  The management, of course. Shareholders are tolerated, but managers rule.(2)"
 
 
     There  can  be  no  justification  for  the  expenditure  of  approximately
$3,000,000  (20% of  Cortech's  net worth) on what we believe is a  self-serving
merger,  without  consulting with Asset Value, who, in our view,  represents the
position of the public stockholders.  Unfortunately,  no matter what the outcome
we  stockholders  will pay the costs of what we consider the sheer  arrogance of
Cortech's management and directors.


              THIS BOARD ACTS LIKE THEIR VOICE IS THE ONLY CHOICE.

     But we  stockholders  can  demonstrate  that they are wrong. We urge you to
read our enclosed  Proxy  Statement and join us in voting AGAINST the Merger and
FOR the removal of the Poison  Pill.  We also  recommend  voting FOR the Reverse
Stock Split.
 
                                            Sincerely,



                                            /s/ Paul O. Koether
                                            -------------------------
                                            Paul O. Koether
                                            Asset Value Fund Limited Partnership



                              VOTE NO TO THE MERGER


                      VOTE YES TO REMOVE THE POISON PILL


                      VOTE YES FOR THE REVERSE STOCK SPLIT



- -------------
     (2) Market Watch, New York Times 3/8/98,  Floyd Norris. This quote has been
made without the permission of the New York Times or Mr. Norris.





                                    IMPORTANT


     If your shares are held in "Street  Name" only your bank or broker can vote
your shares, and only upon receipt of your specific instructions. Please contact
the person  responsible  for your account and  instruct  them to execute a white
proxy card as soon as possible.

     If you have any questions or need further assistance in voting, please call
John W. Galuchie,  Jr., of Asset Value Fund Limited Partnership collect at (908)
234-1881, or our proxy solicitor:
        

                           BEACON HILL PARTNERS, INC.
                                90 BROAD STREET
                            NEW YORK, NEW YORK 10004
                                 (800) 253-3814