SECURITIES AND EXCHANGE COMMISSION
                              Washington, DC 20549

                                  SCHEDULE 13G
                                 (Rule 13d-102)

       INFORMATION TO BE INCLUDED IN THE STATEMENTS FILED
       PURSUANT TO RULES 13d-1(b)(c), AND (d) AND AMENDMENTS THERETO
       FILED PURSUANT TO RULE 13d-2(b)

                                (Amendment No. )*

                                  Aerogen, Inc.
                -----------------------------------------------
                                (Name of Issuer)

                           Common Stock, $.001 par value
--------------------------------------------------------------------------------
                         (Title of Class of Securities)

                                    007779101
                               ------------------
                                 (CUSIP Number)

                               September 10, 2003
--------------------------------------------------------------------------------
            (Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

[ ]     Rule 13d-1(b)
[X]     Rule 13d-1(c)
[ ]     Rule 13d-1(d)

*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).

                                  SCHEDULE 13G
CUSIP NO. 007779101                                                    2 of 6
_____________________________________________________________________________
1    NAMES OF REPORTING PERSONS
     I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (Entities Only)

     Michael A. Roth and Brian J. Stark, as joint filers pursuant to
     Rule 13d-1(k)
_____________________________________________________________________________
2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP       (a) [ ]
     Not Applicable                                         (b) [ ]
_____________________________________________________________________________
3    SEC USE ONLY
_____________________________________________________________________________
4    CITIZENSHIP OR PLACE OF ORGANIZATION

     United States of America
_____________________________________________________________________________

NUMBER OF      5    SOLE VOTING POWER

SHARES              2,278,491
               ______________________________________________________________
BENEFICIALLY   6    SHARED VOTING POWER

OWNED BY            Not Applicable
               ______________________________________________________________
EACH           7    SOLE DISPOSITIVE POWER

REPORTING           2,278,491
               ______________________________________________________________
PERSON         8    SHARED DISPOSITIVE POWER

WITH                Not Applicable
_____________________________________________________________________________
9    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     2,278,491
_____________________________________________________________________________
10   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
     Not Applicable
_____________________________________________________________________________
11   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

     9.9%
_____________________________________________________________________________
12   TYPE OF REPORTING PERSON*

     IN
_____________________________________________________________________________


                                  SCHEDULE 13G
CUSIP NO. 007779101                                                    3 of 6

Item 1(a).     Name of Issuer:

               Aerogen, Inc., a Delaware corporation (the "Issuer").

Item 1(b).     Address of Issuer's Principal Executive Offices:

               2071 Stierlin Court
               Mountain View, CA 94043

Items 2(a),
(b) and (c).   Name of Persons Filing, Address of Principal Business Office and
               Citizenship:

               Michael A. Roth and Brian J. Stark, as joint filers
               (collectively, the "Reporting Persons").

               The principal business office of the Reporting Persons is 3600
               South Lake Drive, St. Francis, WI 53235.

               The Reporting Persons are U.S. citizens.

Item 2(d).     Title of Class of Securities:

               Common Stock, $.001 par value, of the Issuer (the "Common Stock")

Item 2(e).     CUSIP Number:

               007779101

Item 3.        Not applicable.

Item 4.        Ownership.

               (a)  Amount beneficially owned:

                    2,278,491 shares of Common Stock*

               (b)  Percent of class:

                    Based on 20,529,231 shares of Common Stock outstanding as of
                    August 28, 2003, the Reporting Persons beneficially own 9.9%
                    of the issued and outstanding shares of Common Stock.*

               (c)  Number of shares to which such Reporting Persons have:

                    (i)  Sole power to vote or direct the vote: 2,278,491*

                    (ii) Shared power to vote or direct the vote: None

                                  SCHEDULE 13G
CUSIP NO. 007779101                                                    4 of 6

                    (iii) Sole power to dispose or to direct the disposition of:
                          2,278,491*

                    (iv) Shared power to dispose of or direct the disposition
                         of: None

               * The foregoing amount of shares and percentage represent the
               combined indirect holdings of Michael A. Roth and Brian J. Stark,
               as joint filers. All of the foregoing shares are issuable to SF
               Capital Partners, Ltd., a British Virgin Islands company ("SF
               Capital") upon conversion and/or exercise of a convertible
               debenture and warrant issued to it by the Issuer. The terms of
               such warrant and debenture preclude the holder thereof from
               exercising or converting (as applicable) its warrant or debenture
               (as applicable) if such exercise or conversion (as applicable)
               would result in such holder and its affiliates beneficially
               owning in excess of 9.999% of the outstanding shares of Common
               Stock following such exercise or conversion (as applicable).
               Messrs. Roth and Stark are the founding members and direct the
               management of Staro Asset Management, L.L.C., a Wisconsin limited
               liability company ("Staro") which acts as investment manager and
               has sole power to direct the management of SF Capital. Through
               Staro, Messrs. Roth and Stark possess sole voting and dispositive
               power over all of the foregoing shares. Therefore, for the
               purposes of Rule 13d-3 under the Securities Exchange Act of 1934,
               Messrs. Roth and Stark may be deemed to be the beneficial owners
               of the foregoing shares.

Item 5.        Ownership of Five Percent or Less of a Class.

               Not Applicable.

Item 6.        Ownership of More than Five Percent on Behalf of Another Person.

               Not Applicable.

Item 7.        Identification and Classification of the Subsidiary Which
               Acquired the Security Being Reported By the Parent Holding
               Company.

               Not Applicable.

Item 8.        Identification and Classification of Members of the Group.

               Not Applicable.

Item 9.        Notice of Dissolution of a Group.

               Not Applicable.

Item 10.       Certification.

               By signing below I certify that, to the best of my knowledge and
               belief, the securities referred to above were not acquired and
               are not held for the purpose of or with the effect of changing or
               influencing the control of the issuer of the

                                  SCHEDULE 13G
CUSIP NO. 007779101                                                    5 of 6


               securities and were not acquired and are not held in connection
               with or as a participant in any transaction having that purpose
               or effect.


                                  SCHEDULE 13G
CUSIP NO. 007779101                                                    6 of 6

                                   SIGNATURE

     After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.

Dated:   September 19, 2003

                                /s/ Michael A. Roth
                                -----------------------
                                Michael A. Roth


                                /s/ Brian J. Stark
                                -----------------------
                                Brian J. Stark


                                  SCHEDULE 13G
CUSIP NO. 007779101


                                                                       Exhibit 1

                             JOINT FILING AGREEMENT

          In accordance with Rule 13d 1(k) under the Securities Exchange Act of
     1934, as amended, the undersigned agree to the joint filing on behalf of
     each of them of a statement on Schedule 13G (including amendments thereto)
     with respect to certain shares of Common Stock, $.001 par value of Aerogen,
     Inc. and further agree that this Joint Filing Agreement shall be included
     as an exhibit to such joint filings.

          The undersigned further agree that each party hereto is responsible
     for the timely filing of such Schedule 13G and any amendments thereto, and
     for the completeness and accuracy of the information concerning such party
     contained therein; provided, however, that no party is responsible for the
     completeness or accuracy of the information concerning any other party
     making the filing, unless such party knows or has reason to believe that
     such information is inaccurate.

     IN WITNESS WHEREOF, the parties have executed this Joint Filing Agreement
on September 19, 2003.


                                /s/ Michael A. Roth
                                -----------------------
                                Michael A. Roth


                                /s/ Brian J. Stark
                                -----------------------
                                Brian J. Stark