Exhibit 99.2

                                  [LETTERHEAD]
                                Human BioSystems


August 8, 2005

Re:Human BioSystems Common Stock

Dear Human BioSystems Reg S Shareholder:

Human BioSystems issued a press release on July 19, 2005 regarding the exchange
of Reg S stock trading under WKN#164580 for New Stock. The press release is
repeated below with new changes in procedure. Please read it carefully as we are
now instructing you to send the Reg S shares directly to our transfer agent,
First American Stock Transfer in the U.S. You may contact our Trustee, Mr.
Karsten Behrens, who is German and can answer your questions. Mr. Behren's
office phone number in Switzerland is 41-219-222-472.

It has come to our attention that Reg S shares of the common stock of Human
BioSystems, a California corporation ("HBS"), may have been sold without the
authorization of HBS. The unauthorized issuance of HBS shares may have
tainted the market for those HBS shares previously issued under Regulation S
under the United States Securities Act of 1933, as amended, and currently
trading under WKN#164580 the ("Reg S Stock").

In order to halt these unauthorized issuances, we are undertaking an exchange
offer (the "Offer") to exchange one share of HBS common stock (the "New Stock")
for each share of Reg S Stock outstanding before or upon the de-listing date
(the "Record Date") when the Reg S Stock is no longer tradable.   Each share of
New Stock will be registered no later than six months from the date hereof for
trading on the United States Over-the-Counter Bulletin Board market (the
"OTCBB").

In order to accept the Offer, you must return your Reg S stock to our transfer
agent, First American Stock Transfer together with a copy of the brokerage
account receipt showing the date of purchase and the number of shares of Reg S
stock purchased.  Please instruct your broker/bank to send your Reg S shares
electronically to First American Stock Transfer in the U.S. through the ATOP
system, which is known to your bank or broker. An account has been established
at the transfer agent to accept the Reg S shares.

Please fax your brokerage account receipt to both Human BioSystems at (650)
327-8658 and to First American Stock Transfer at (602) 788-0423, indicating the
name of the holder of the Reg S Stock and the number of shares held. If possible
please also include your telephone and fax number, and your email address so
that we may communicate with you if there are questions.

THIS EXCHANGE OFFER EXPIRES ON DECEMBER 29, 2005.  Human BioSystems reserves the
right to refuse to exchange any Reg S Stock of unauthorized origin.  Upon
receipt of the Reg S Stock and documentation indicating the purchase of
authorized Reg S Stock, we will send you a certificate for the same number of
shares of New Stock within 30 business days.  If shares of Reg S Stock, together
with the required documentation, are not tendered for exchange by December 29,
2005, they will no longer be exchangeable for New Stock.  In addition, as we
plan to de-list the Reg S Stock from trading on all German stock exchanges as
soon as possible following this news release, the Reg S Stock will no longer be
tradeable effective immediately upon such de-listing.

This Exchange Offer will also be submitted to Clearstream and Euroclear for
distribution so that we may reach as many Reg S Shareholders as possible.

Thank you for your investment in and support of Human BioSystems.  Due to your
investment, we have made significant progress toward achieving our goals to
date.

Please contact our Trustee, Mr. Karsten Behrens or me if you have any questions
or comments regarding this matter.

					Very truly yours,

					/s/
					___________________________
					 Harry Masuda
					 President and CEO

cc: Cathryn S. Gawne, Esq.
    Mr. Karsten Behrens
    Clearstream
    Euroclear
    DTC