<PAGE>

                                  United States
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549


                                  FORM 10-QSB


[X]               QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
                  SECURITIES EXCHANGE ACT OF 1934


For the quarterly period ended     MARCH 31, 2003
                               ----------------------


[ ]               TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
                  SECURITIES EXCHANGE ACT OF 1934

                         Commission File Number 0-20791


                           AMARILLO BIOSCIENCES, INC.
--------------------------------------------------------------------------------
        (Exact name of small business issuer as specified in its charter)

              TEXAS                                       75-1974352
--------------------------------------------------------------------------------
(State or other jurisdiction of                (IRS Employer Identification No.)
 incorporation or organization)

     800 West Ninth, Amarillo, Texas                                    79101
--------------------------------------------------------------------------------
(Address of principal executive offices)                              (Zip Code)

                  806-376-1741                                  FAX 806-376-9301
--------------------------------------------------------------------------------
(Issuer's telephone number, including area code)


         Check whether the issuer (1) filed all reports required to be filed by
Section 13 or 15(d) of the Exchange Act during the past 12 months (or for such
shorter period that the registrant was required to file such reports), and (2)
has been subject to such filing requirements for the past 90 days.
Yes [X].  No[ ].

As of March 31, 2003 there were 8,994,072 shares of the issuer's common stock
outstanding.



<PAGE>

                           AMARILLO BIOSCIENCES, INC.


                                      INDEX


<Table>
<Caption>
                                                                                                         PAGE NO.
                                                                                                         --------
<S>                  <C>                                                                                 <C>
PART I:              FINANCIAL INFORMATION

ITEM 1.              Financial Statements

                     Consolidated Balance Sheet - March 31, 2003 .......................................        3

                     Consolidated Statements of Operations - Three Months Ended
                     March 31, 2003 and March 31, 2002 .................................................        4

                     Condensed Consolidated Statements of Cash Flows - Three
                     Months Ended March 31, 2003 and 2002 ..............................................        5

                     Notes to Consolidated Financial Statements ........................................        6

ITEM 2.              Management's Plan of Operations ...................................................        6

ITEM 3.              Controls and Procedures ...........................................................        9

PART II:             OTHER INFORMATION

ITEM 6.              Exhibits and Reports on Form 8-K ..................................................       10

Signatures .............................................................................................       11
</Table>



                                       2
<PAGE>

                         PART I - FINANCIAL INFORMATION

ITEM 1. FINANCIAL STATEMENTS

                   Amarillo Biosciences, Inc. and Subsidiaries
                           Consolidated Balance Sheets
                                 March 31, 2003

<Table>
<S>                                                                <C>
ASSETS
Current assets:
   Cash                                                            $     14,584
   Other current assets                                                   3,443
                                                                   ------------
Total current assets                                                     18,027

Property and equipment, net                                               1,616
Patents, net of accumulated amortization of $134,412                    162,723
                                                                   ------------
Total assets                                                       $    182,366
                                                                   ============

LIABILITIES AND STOCKHOLDERS' DEFICIT
Current liabilities:
   Accounts payable                                                $    865,080
   Accrued interest expense                                             287,137
   Accrued payroll expense                                               46,542
   Other accrued expense                                                   (537)
                                                                   ------------
Total current liabilities                                             1,198,222

Notes payable to stockholders                                         2,090,000
                                                                   ------------
Total liabilities                                                     3,288,222

Commitments and contingencies

Stockholders' deficit
   Preferred stock, $.01 par value:
      Authorized shares - 10,000,000
      Issued shares - none                                                   --
   Common stock, $.01 par value:
      Authorized shares - 20,000,000
      Issued shares - 8,994,072                                          89,941
   Additional paid-in capital                                        18,923,182
   Accumulated deficit                                              (22,118,979)
                                                                   ------------
Total stockholders' deficit                                          (3,105,856)
                                                                   ------------
Total liabilities and stockholders' deficit                        $    182,366
                                                                   ============
</Table>



                                       3
<PAGE>
                   Amarillo Biosciences, Inc. and Subsidiaries
                      Consolidated Statements of Operations

<Table>
<Caption>
                                                    THREE MONTHS ENDED MARCH 31,
                                                       2003              2002
                                                   ------------      ------------
<S>                                                <C>               <C>
Revenues:
   Dietary supplement sales                        $      4,806      $        561
   Interferon sales                                      10,000                --
   Interest income                                           --             1,090
   Federal research grants                                6,586             8,360
   Gain on sale of building and equipment                34,790                --
   Other                                                  4,505             1,766
                                                   ------------      ------------
                                                         60,687            11,777
Expenses:
   Research and development expenses                     40,292           179,765
   Selling, general and administrative
     expenses                                            37,187            47,425
   Interest expense                                      22,554            23,826
                                                   ------------      ------------
                                                        100,033           251,016
                                                   ------------      ------------

Net loss                                           $    (39,346)     $   (239,239)
                                                   ============      ============

Basic and diluted net loss per share               $     (0.004)     $      (0.03)
                                                   ============      ============

Weighted average shares outstanding                   8,994,072         8,843,912
                                                   ============      ============
</Table>



                                       4
<PAGE>

                   Amarillo Biosciences, Inc. and Subsidiaries
                 Condensed Consolidated Statements of Cash Flows

<Table>
<Caption>
                                                                 Three months ended
                                                                      March 31,
                                                              --------------------------
                                                                 2003            2002
                                                              ----------      ----------
<S>                                                           <C>             <C>
Net cash used in operating activities                         $  (69,362)     $ (337,415)
                                                              ----------      ----------

Cash provided by (used in) investing activities                  119,836          (5,381)
                                                              ----------      ----------

Cash from financing activities:
   Proceeds from notes payable                                    45,000              --
   Repayments of notes payable                                   (80,990)         (1,397)
   Issuance of common stock                                           --         500,000
                                                              ----------      ----------
      Net cash provided by (used in) financing activities        (35,990)        498,603
                                                              ----------      ----------
Net increase (decrease) in cash and cash equivalents              14,484         155,807
                                                              ----------      ----------
Cash and cash equivalents at beginning of period                     100          68,318
                                                              ----------      ----------
Cash and cash equivalents at end of period                    $   14,584      $  224,125
                                                              ==========      ==========
Supplemental Disclosure of Cash Flow Information

Cash paid for income taxes                                    $       --      $       --
                                                              ==========      ==========

Cash paid for interest                                        $    1,768      $    2,171
                                                              ==========      ==========
</Table>



                                       5
<PAGE>

                   AMARILLO BIOSCIENCES, INC. AND SUBSIDIARIES


              NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

1.   Basis of presentation. The accompanying consolidated financial statements,
     which should be read in conjunction with the consolidated financial
     statements and footnotes included in the Company's Form 10-KSB for the year
     ended December 31, 2002 filed with the Securities and Exchange Commission,
     are unaudited, but have been prepared in accordance with accounting
     principles generally accepted in the United States for interim financial
     information. Accordingly, they do not include all of the information and
     footnotes required by accounting principles generally accepted in the
     United States for complete financial statements. In the opinion of
     management, all adjustments (consisting only of normal recurring
     adjustments) considered necessary for a fair presentation have been
     included.

     Operating results for the three months ended March 31, 2003 are not
     necessarily indicative of the results that may be expected for the full
     year ending December 31, 2003.

2.   Loss per share. Loss per share is computed based on the weighted average
     number of common shares outstanding.

3.   Recent Accounting Pronouncements. In December 2002, the FASB issued
     Statements of Financial Accounting Standards No. 148 "Accounting for
     Stock-Based Compensation----Transition and Disclosure----an amendment of
     FASB Statement No. 123", This Statement amends FASB Statement No. 123,
     Accounting for Stock-Based Compensation, to provide alternative methods of
     transition for a voluntary change to the fair value based method of
     accounting for stock-based employee compensation. In addition, this
     Statement amends the disclosure requirements of Statement 123 to require
     prominent disclosures in both annual and interim financial statements about
     the method of accounting for stock-based employee compensation and the
     effect of the method used on reported results. The adoption of SFAS 148 is
     not expected to have a material effect on the Company's financial position
     or results of its operations. There is no pro forma disclosure as of March
     31, 2003 since all options are fully vested as of 12/31/02.


ITEM 2. MANAGEMENT'S PLAN OF OPERATIONS

The Company's Management has developed a Plan of Operations for 2003. The
Company continues to engage in research and development activities focused on
developing biologics for the treatment of human and animal diseases. The Company
has not commenced any significant product commercialization and, until such time
as it does, will not generate significant product revenues. The Company's
accumulated deficit has continued to grow, from $22,080,000 at December 31, 2002
to $22,119,000 at March 31,



                                       6
<PAGE>

2003. Operating losses are expected to continue for the foreseeable future and
until such time as the Company is able to attain sales levels sufficient to
support its operations.

As of March 31, 2003, the Company had current assets of $18,027, including cash
in the amount of $14,584. The Company will need to raise additional capital in
order to implement its plan of operations.

During the next 12 months the Company will continue its research and development
activities, as well as the activities necessary to develop commercial
partnerships and licenses and to continue nutraceutical sales. The Company's
expenditure of financial resources during this period will fall principally into
five broad categories, as follows: Research and Development; Personnel;
Consulting and Professional (other than legal and accounting); Legal and
Accounting; and Public Relations, Investor Relations and Shareholder Relations.
The Company's expectations and goals with respect to these categories are
addressed separately below, by category.

REVENUES FROM SALES OF DIETARY SUPPLEMENT: The Company had sales of anhydrous
crystalline maltose (ACM), marketed locally as Maxisal(R), generating $4,806 in
the first quarter of 2003.

REVENUES FROM INTERFERON SALES: There were $10,000 of interferon sales in the
first quarter of 2003.

RESEARCH AND DEVELOPMENT: Until it achieves commercial product sales, the
Company's business is research and development, and this is the area in which
the Company's principal efforts will be expended during 2003. The Company has
budgeted approximately $296,389 for expenditure for the balance of the year on
research and development, the expenditure of this amount will be subject to
raising additional funds. The Company expended $40,292 in the first quarter of
2003 for specific research and development, projects; such amount does not
include general administrative costs, or expenditures described under other
categories below.

PERSONNEL: In addition to its intellectual property, the Company's principal
assets are its personnel. The Company has been successful in controlling its
personnel costs, both by maintaining its principal location in Amarillo, Texas,
and by ensuring maximum efficiency and utilization of existing personnel. The
Company has budgeted approximately $275,489 for personnel expenses during 2003,
including salaries, payroll taxes, and group health, insurance. The projected
amount does not include adding employees. Also, in lieu of cash compensation,
the Company may issue stock options or other equity instruments to selected
employees in fiscal 2003. The Company expended $68,067 for personnel in the
first quarter of 2003.

At the present time, the President and CEO of the Company, Joseph M. Cummins, is
also serving as the Company's Chief Financial Officer (CFO).



                                       7
<PAGE>

CONSULTING AND PROFESSIONAL (EXCEPT LEGAL AND ACCOUNTING): The Company has
budgeted approximately $12,000 for expenditure on professional consultants in
2003. Consulting fees are expected to be paid to a number of independent
consultants in connection with the operation of the Company and to certain
directors who perform specific consulting tasks at the Company's request. The
Company will continue to use the services of consultants to complement the
Company's small full-time staff, where such is a more efficient utilization of
the Company's resources. The Company expended $227 in the first quarter of 2003
for consulting and professional fees.

LEGAL AND ACCOUNTING: Although the Company is not involved in litigation, it has
budgeted legal expenses of approximately $100,000 in 2003. Approximately 20% of
the Company's legal expenditures will be for preparation and filing of patents
and for maintenance of existing patents in a number of countries. Other legal
expenses will be related to compliance with laws and regulations affecting
public companies, licensing and contracting and general corporate matters. The
Company does not presently have an in-house legal staff, nor does it intend to
put such a staff in place in 2003. The Company has budgeted $18,000 for
accounting expense in 2003 and expects to use Malone & Bailey, PLLC as its
independent auditors. The Company incurred $4,992 for legal and $6,000 for
accounting fees in the first quarter of 2003.

PUBLIC RELATIONS, INVESTOR RELATIONS AND SHAREHOLDER RELATIONS: The Company has
budgeted approximately $5,000 for public relations, investor relations and
shareholder relations during 2003. The Company has also budgeted sufficient
amounts to maintain its comprehensive web site (www.amarbio.com).

LIQUIDITY NEEDS: At March 31, 2003, the Company had available cash of
approximately $14,584, and had a working capital deficit of approximately
$1,180,195. The Company's continued losses and lack of liquidity indicate that
the Company may not be able to continue as a going concern for a reasonable
period of time. The Company's ability to continue as a going concern is
dependent upon several factors including, but not limited to, the Company's
ability to generate sufficient cash flows to meet its obligations on a timely
basis, obtain additional financing and continue to obtain supplies and services
from its vendors. The Company will need to raise additional funds in order to
fully execute its 2003 Plan. The Company is presently negotiating with human
health and animal health commercial development partners in various regions of
the world including the United States, Canada, Europe and the Middle East. The
Company believes that one or more of these agreements will be executed during
2003. These agreements could generally include provisions for the commercial
partner to pay ABI a technology access fee, could include payments for a portion
of the clinical trial expenses, could include payment obligations to ABI upon
the accomplishment of certain defined tasks and/or could provide for payments
relating to the future sales of commercial product. These agreements could be an
important source of funds for ABI. However, there can be no assurance that the
Company will be successful in obtaining additional funding from either human
health and animal health commercial development partners or private investors.
If the Company is not successful in raising additional funds, it will need to
significantly curtail clinical trial expenditures and to further reduce staff
and administrative expenses and may be forced to cease operations.



                                       8
<PAGE>

FORWARD-LOOKING STATEMENTS

Certain statements made in this Plan of Operations and elsewhere in this report
are "forward-looking statements" within the meaning of the Private Securities
Litigation Reform Act of 1995 (the "Act"). Forward-looking statements include,
without limitation, any statement that may predict, forecast, indicate or imply
future results, performance, achievements, costs or expenses and may contain
words such as "believe," "anticipate," "expect," "estimate," "project,"
"budget," or words or phrases of similar meaning. Forward-looking statements
involve risks and uncertainties which may cause actual results to differ
materially from those projected in the forward-looking statements. Such risks
and uncertainties are detailed from time to time in reports filed by the Company
with the Securities and Exchange Commission, including Forms 8-K, 10-QSB and
10-KSB and include among others the following: promulgation and implementation
of regulations by the U.S. Food and Drug Administration ("FDA"); promulgation
and implementation of regulations by foreign governmental instrumentalities with
functions similar to those of the FDA; costs of research and development and
clinical trials, including without limitation, costs of clinical supplies,
packaging and inserts, patient recruitment, trial monitoring, trial evaluation
and publication; and possible difficulties in enrolling a sufficient number of
qualified patients for certain clinical trials. The Company is also dependent
upon a broad range of general economic and financial risks, such as possible
increases in the costs of employing and/or retaining qualified personnel and
consultants and possible inflation which might affect the Company's ability to
remain within its budget forecasts. The principal uncertainties to which the
Company is presently subject are its inability to ensure that the results of
trials performed by the Company will be sufficiently favorable to ensure
eventual regulatory approval for commercial sales, its inability to accurately
budget at this time the possible costs associated with hiring and retaining of
additional personnel, uncertainties regarding the terms and timing of one or
more commercial partner agreements and its ability to continue as a going
concern.

The risks cited here are not exhaustive. Other sections of this report may
include additional factors which could adversely impact the Company's business
and future prospects. Moreover, the Company is engaged in a very competitive and
rapidly changing industry. New risk factors emerge from time to time and it is
not possible for management to predict all such risk factors, nor can it assess
the impact of all such risk factors on the Company's business, or the extent to
which any factor or combination of factors may cause actual results to differ
materially from those projected in any forward-looking statements. Given these
risks and uncertainties, investors should not place undue reliance on
forward-looking statements as a prediction of actual future events.


ITEM 3. CONTROLS AND PROCEDURES

Based on the evaluation conducted by Dr. Joseph M. Cummins, both the Chief
Executive Officer ("CEO") and Chief Financial Officer ("CFO"), as of a date
within 90 days of the filing date of this quarterly report ("Evaluation Date"),
of the effectiveness of the Company's disclosure controls and procedures, Dr.
Joseph M. Cummins concluded that, as of the Evaluation Date, (1) there were no
significant deficiencies or material



                                       9
<PAGE>

weaknesses in the Company's disclosure controls and procedures, (2) there were
no significant changes in internal controls or in other factors that could
significantly affect internal controls subsequent to the Evaluation Date and (3)
no corrective actions were required to be taken.


                           PART II - OTHER INFORMATION


ITEM 6. EXHIBITS AND REPORTS ON FORM 8-K.

                  No reports on Form 8-K were filed during the quarter ended
                  March 31, 2003.



                                       10
<PAGE>

                                   SIGNATURES



                  Pursuant to the requirements of Securities Exchange Act of
1934, the Registrant has duly caused this report to be signed on its behalf by
the undersigned thereunto duly authorized.



                                       AMARILLO BIOSCIENCES, INC.


Date: May 15, 2003                     By:  /s/ Joseph M. Cummins
                                          --------------------------------------
                                            Joseph M. Cummins
                                            President, Chief Executive Officer
                                            and Chief Financial Officer


                            CERTIFICATION PURSUANT TO
                             18 U.S.C. SECTION 1350
                             AS ADOPTED PURSUANT TO
                  SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of Amarillo Biosciences, Inc. on Form
10-QSB for the period ended March 31, 2003 as filed with the Securities and
Exchange Commission on the date hereof (the "Report"), each of the undersigned,
in the capacities and on the dates indicated below, hereby certifies pursuant to
18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley
Act of 2002, that to the best of his knowledge:

1. The Report fully complies with the requirements of Section 13(a) or 15(d) of
the Securities Exchange Act of 1934; and

2. The information contained in the Report fairly presents, in all material
respects, the financial condition and results of operation of the Company.



Date: May 15, 2003                     By:  /s/ Joseph M. Cummins
                                          --------------------------------------
                                            Joseph M. Cummins
                                            President, Chief Executive Officer
                                            and Chief Financial Officer



<PAGE>

                              FORM OF CERTIFICATION
                       PURSUANT TO RULE 13A-14 AND 15D-14
              UNDER THE SECURITIES EXCHANGE ACT OF 1934, AS AMENDED

                                  CERTIFICATION

         I, Joseph M. Cummins, certify that:

         1. I have reviewed this quarterly report on Form 10-QSB of Amarillo
Biosciences, Inc.;

         2. Based on my knowledge, this quarterly report does not contain any
untrue statement of material fact or omit to state a material fact necessary to
make the statements made, in light of the circumstances under which such
statements were made, not misleading with respect to the period covered by this
quarterly report;

         3. Based on my knowledge, the financial statements, and other financial
information included in this quarterly report, fairly present in all material
respects the financial condition, results of operations and cash flows of the
registrant as of, and for, the periods presented in this quarterly report;

         4. I am responsible for establishing and maintaining disclosure
controls and procedures (as defined in Exchange Act Rules 13a-14 and 15d-14) for
the registrant and have:

                  (a) designed such disclosure controls and procedures to ensure
that material information relating to the registrant, including its consolidated
subsidiaries, is made known to us by others within those entities, particularly
during the period in which this quarterly report is being prepared;

                  (b) evaluated the effectiveness of the registrant's disclosure
controls and procedures as of a date within 90 days of the filing date of this
quarterly report (the "Evaluation Date"); and

                  (c) presented in this quarterly report our conclusions about
the effectiveness of the disclosure controls and procedures based on our
evaluation as of the Evaluation Date;

         5. As the registrant's certifying officer I have disclosed, based on
the most recent evaluation, to the registrant's auditors and the audit committee
of the registrant's board of directors (or persons performing the equivalent
functions):

                  (a) all significant deficiencies in the design or operation of
internal controls which could adversely affect the registrant's ability to
record, process, summarize, and report financial data and have identified for
the registrant's auditors any material weaknesses in internal controls; and

                  (b) any fraud, whether or not material, that involves
management or other employees who have a significant role in the registrant's
internal controls.

         6. I have indicated in this quarterly report whether or not there were
significant changes in internal controls or in other factors that could
significantly affect internal controls subsequent to the date of our most recent
evaluation, including any corrective actions with regard to significant
deficiencies and material weaknesses.


Date: May 15, 2003                           /s/ Joseph M. Cummins
                                       -----------------------------------------
                                       Name: Joseph M. Cummins
                                       Title: President, Chief Executive Officer
                                               and Chief Financial Officer