UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549


                                  SCHEDULE 13G

                    Under the Securities Exchange Act of 1934


                           Medistem Laboratories, Inc.
--------------------------------------------------------------------------------
                                (Name of Issuer)


                    Common Stock, par value $0.0001 per share
--------------------------------------------------------------------------------
                         (Title of Class of Securities)


                                   58501F 10 8
                    -----------------------------------------
                                 (CUSIP Number)


                                February 3, 2006
--------------------------------------------------------------------------------
             (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).



--------------------------                                ----------------------
CUSIP No.  58501F 10 8            SCHEDULE 13G              Page 2 of 9 Pages
--------------------------                                ----------------------

--------------------------------------------------------------------------------
1    NAME OF REPORTING PERSON
     S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

     Vision Opportunity Master Fund, Ltd.
--------------------------------------------------------------------------------
2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                         (a) [ ]
                                                                         (b) [ ]
--------------------------------------------------------------------------------
3    SEC USE ONLY
--------------------------------------------------------------------------------
4    CITIZENSHIP OR PLACE OF ORGANIZATION

     Cayman Islands
--------------------------------------------------------------------------------
NUMBER OF                    5    SOLE VOTING POWER
SHARES
BENEFICIALLY                      0
OWNED BY                     ---------------------------------------------------
EACH                         6    SHARED VOTING POWER
REPORTING
PERSON                            14,236,466
WITH                         ---------------------------------------------------
                             7    SOLE DISPOSITIVE POWER

                                  0
                             ---------------------------------------------------
                             8    SHARED DISPOSITIVE POWER

                                  14,236,466
--------------------------------------------------------------------------------
9    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     14,236,466
--------------------------------------------------------------------------------
10   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES *
                                                                             [ ]
--------------------------------------------------------------------------------
11   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

     9.99%
--------------------------------------------------------------------------------
12   TYPE OF REPORTING PERSON *

     CO
--------------------------------------------------------------------------------



--------------------------                                ----------------------
CUSIP No.  58501F 10 8            SCHEDULE 13G              Page 3 of 9 Pages
--------------------------                                ----------------------

--------------------------------------------------------------------------------
1    NAME OF REPORTING PERSON
     S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

     Vision Capital Advisors, LLC (formerly known as Vision Opportunity Capital
     Management, LLC)
--------------------------------------------------------------------------------
2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                         (a) [ ]
                                                                         (b) [ ]
--------------------------------------------------------------------------------
3    SEC USE ONLY
--------------------------------------------------------------------------------
4    CITIZENSHIP OR PLACE OF ORGANIZATION

     Delaware
--------------------------------------------------------------------------------
NUMBER OF                    5    SOLE VOTING POWER
SHARES
BENEFICIALLY                      0
OWNED BY                     ---------------------------------------------------
EACH                         6    SHARED VOTING POWER
REPORTING
PERSON                            14,236,466
WITH                         ---------------------------------------------------
                             7    SOLE DISPOSITIVE POWER

                                  0
                             ---------------------------------------------------
                             8    SHARED DISPOSITIVE POWER

                                  14,236,466
--------------------------------------------------------------------------------
9    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     14,236,466
--------------------------------------------------------------------------------
10   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES *
                                                                             [ ]
--------------------------------------------------------------------------------
11   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

     9.99%
--------------------------------------------------------------------------------
12   TYPE OF REPORTING PERSON *

     IA
--------------------------------------------------------------------------------



--------------------------                                ----------------------
CUSIP No.  58501F 10 8            SCHEDULE 13G              Page 4 of 9 Pages
--------------------------                                ----------------------

--------------------------------------------------------------------------------
1    NAME OF REPORTING PERSON
     S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

     Adam Benowitz
--------------------------------------------------------------------------------
2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                         (a) [ ]
                                                                         (b) [ ]
--------------------------------------------------------------------------------
3    SEC USE ONLY
--------------------------------------------------------------------------------
4    CITIZENSHIP OR PLACE OF ORGANIZATION

     US Citizen
--------------------------------------------------------------------------------
NUMBER OF                    5    SOLE VOTING POWER
SHARES
BENEFICIALLY                      0
OWNED BY                     ---------------------------------------------------
EACH                         6    SHARED VOTING POWER
REPORTING
PERSON                            14,236,466
WITH                         ---------------------------------------------------
                             7    SOLE DISPOSITIVE POWER

                                  0
                             ---------------------------------------------------
                             8    SHARED DISPOSITIVE POWER

                                  14,236,466
--------------------------------------------------------------------------------
9    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     14,236,466
--------------------------------------------------------------------------------
10   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES *
                                                                             [ ]
--------------------------------------------------------------------------------
11   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

     9.99%
--------------------------------------------------------------------------------
12   TYPE OF REPORTING PERSON *

     IN
--------------------------------------------------------------------------------



--------------------------                                ----------------------
CUSIP No.  58501F 10 8            SCHEDULE 13G              Page 5 of 9 Pages
--------------------------                                ----------------------


Item 1(a).    Name of Issuer:

                  Medistem Laboratories, Inc.

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

                  2027 E. Cedar St., Suite 102
                  Tempe, Arizona 85281

Item 2(a).    Name of Person Filing.
                  Vision Opportunity Master Fund, Ltd.
                  Vision Capital Advisors, LLC
                  Adam Benowitz

Item 2(b).    Address of Principal Business Office or, if None, Residence.
                  Vision Opportunity Master Fund, Ltd.:

                    c/o Citi Hedge Fund Services (Cayman) Limited
                    P.O. Box 1748
                    Cayman Corporate Centre
                    27 Hospital Road, 5th Floor
                    Grand Cayman KY1-1109
                    Cayman Islands

                  Vision Capital Advisors, LLC
                  Adam Benowitz:

                    20 W. 55th Street, 5th Floor
                    New York, New York 10019
                    USA

Item 2(c).    Citizenship.

                  Vision Opportunity Master Fund, Ltd. - Cayman Islands
                  Vision Capital Advisors, LLC - Delaware
                  Adam Benowitz - US Citizen

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

                  Common Stock, par value $0.0001 per share

Item 2(e).    CUSIP Number:

                  58501F 10 8

Item 3.       If this statement is filed pursuant to  ss.ss.240.13d-1(b)
              or 240.13d-2(b) or (c), check whether the person filing is a:

                  Not Applicable



--------------------------                                ----------------------
CUSIP No.  58501F 10 8            SCHEDULE 13G              Page 6 of 9 Pages
--------------------------                                ----------------------


Item 4.       Ownership.

         The following is information regarding the aggregate number and
         percentage of the class of securities of the Issuer identified in Item
         1 as of September 12, 2007:

(a)      Vision Opportunity Master Fund, Ltd. - 14,236,466
         Vision Capital Advisors, LLC - 14,236,466
         Adam Benowitz - 14,236,466


(b)      Percent of class:

         Vision Opportunity Master Fund, Ltd. - 9.99%*
         Vision Capital Advisors, LLC - 9.99%*
         Adam Benowitz - 9.99%*

(c)      Number of shares as to which the person has:

         Vision Opportunity Master Fund, Ltd.
         ------------------------------------

         (i)      Sole power to vote or to direct the vote: 0
         (ii)     Shared power to vote or to direct the vote: 14,236,466
         (iii)    Sole power to dispose or to direct the disposition of: 0
         (iv)     Shared power to dispose or to direct the disposition of:
                  14,236,466

         Vision Capital Advisors, LLC
         ----------------------------

         (i)      Sole power to vote or to direct the vote: 0
         (ii)     Shared power to vote or to direct the vote: 14,236,466
         (iii)    Sole power to dispose or to direct the disposition of: 0
         (iv)     Shared power to dispose or to direct the disposition of:
                  14,236,466

         Adam Benowitz
         -------------

         (i)      Sole power to vote or to direct the vote: 0
         (ii)     Shared power to vote or to direct the vote: 14,236,466
         (iii)    Sole power to dispose or to direct the disposition of: 0
         (iv)     Shared power to dispose or to direct the disposition of:
                  14,236,466


* Percent of class based on 132,955,693 shares of Common Stock outstanding as of
July 30, 2007 as reported on the Issuer's quarterly report on Form 10-QSB filed
on August 10, 2007.



--------------------------                                ----------------------
CUSIP No.  58501F 10 8            SCHEDULE 13G              Page 7 of 9 Pages
--------------------------                                ----------------------


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 on 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 Group.

                  Not Applicable





--------------------------                                ----------------------
CUSIP No.  58501F 10 8            SCHEDULE 13G              Page 8 of 9 Pages
--------------------------                                ----------------------


Item 10.      Certification.

Certification pursuant to ss.240.13d-1(c):

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





--------------------------                                ----------------------
CUSIP No.  58501F 10 8            SCHEDULE 13G              Page 9 of 9 Pages
--------------------------                                ----------------------


                                    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 12, 2007

                                       VISION OPPORTUNITY MASTER FUND, LTD.**

                                       By: /s/ ADAM BENOWITZ
                                           -------------------------------------
                                           Name:  Adam Benowitz
                                           Title: Portfolio Manager


                                       VISION CAPITAL ADVISORS, LLC**

                                       By: /s/ ADAM BENOWITZ
                                           -------------------------------------
                                           Name:  Adam Benowitz
                                           Title: Managing Member


                                       /s/ ADAM BENOWITZ
                                       -----------------------------------------
                                       ADAM BENOWITZ**


** Vision Capital Advisors, LLC (the "Investment Manager") serves as investment
manager to Vision Opportunity Master Fund, Ltd. (the "Master Fund"), the record
owner of the subject securities. Adam Benowitz is the managing member of the
Investment Manager and the Master Fund's portfolio manager. Each Reporting
Person disclaims beneficial ownership of all securities other than those owned
of record by such Reporting Person.



                                  EXHIBIT INDEX

Exhibit No.       Document
-----------       -----------------------------------------

    1             Joint Filing Agreement





                                    Exhibit 1

                             JOINT FILING AGREEMENT


         In accordance with Rule 13d-1(k) under the Securities Exchange Act of
1934, as amended, the persons named below agree to the joint filing on behalf of
each of them of a statement on Schedule 13G (including amendments thereto) with
respect to the Common Stock, par value $0.0001 per share, of Medistem
Laboratories, Inc. and further agree that this Joint Filing Agreement be
included as an Exhibit to such joint filing.


         Dated: September 12, 2007


                                       VISION OPPORTUNITY MASTER FUND, LTD.

                                       By: /s/ ADAM BENOWITZ
                                           -------------------------------------
                                           Name:  Adam Benowitz
                                           Title: Portfolio Manager


                                       VISION CAPITAL ADVISORS, LLC

                                       By: /s/ ADAM BENOWITZ
                                           -------------------------------------
                                           Name:  Adam Benowitz
                                           Title: Managing Member


                                       /s/ ADAM BENOWITZ
                                       -----------------------------------------
                                       ADAM BENOWITZ