<PAGE>   1
                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                                    FORM 10-Q

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

         FOR THE QUARTERLY PERIOD ENDED MARCH 31, 2000

                                       OR

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

         FOR THE TRANSITION PERIOD FROM _______________ TO _____________

                         COMMISSION FILE NUMBER 0-20096

                                  GLIATECH INC.
             (Exact name of registrant as specified in its charter)

             DELAWARE                                     34-1587242
(State or other jurisdiction                (I.R.S. Employer Identification No.)
 of incorporation or organization)

        23420 COMMERCE PARK ROAD
        CLEVELAND, OHIO                                     44122
(Address of principal executive offices)                 (Zip Code)

                                 (216) 831-3200
              (Registrant's telephone number, including area code)

Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15 (d) of the Securities Exchange Act of 1934
during the preceding 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
                                                         -----       ------

The number of shares outstanding of the registrant's Common Stock, $0.01 par
value per share, as of May 9, 2000 was 9,511,087 shares.


<PAGE>   2


                         GLIATECH INC. AND SUBSIDIARIES

                                      INDEX

PART I.                        FINANCIAL INFORMATION                    PAGE
                                                                        ----

Item 1    Financial Statements:

          Consolidated Balance Sheets -
          March 31, 2000 and December 31, 1999 (unaudited)

          Consolidated Statements of Income -
          for the three months ended March 31, 2000 and 1999 (unaudited)

          Consolidated Statements of Cash Flows -
          for the three months ended March 31, 2000 and 1999 (unaudited)

          Notes to Consolidated Financial Statements

Item 2    Management's Discussion and Analysis of Financial Condition
          and Results of Operations

Item 3    Quantitative and Qualitative Disclosures About Market Risk

PART II.                   OTHER INFORMATION

Item 1    Legal Proceedings

Item 6    Exhibits and Reports on Form 8-K



<PAGE>   3
<TABLE>
<CAPTION>


                         PART I - FINANCIAL INFORMATION

                          ITEM 1. FINANCIAL STATEMENTS

                         GLIATECH INC. AND SUBSIDIARIES
                           CONSOLIDATED BALANCE SHEETS

                                   (unaudited)

                                                                                      MARCH 31,             DECEMBER 31,
                                                                                        2000                     1999
                                                                                   ------------             ------------

<S>                                                                                <C>                      <C>
ASSETS
Current assets:
        Cash and cash equivalents                                                  $  7,555,685             $  3,350,245
        Short-term investments                                                        8,070,543               15,750,620
        Accounts receivable, net                                                      3,109,233                  899,696
        Government grants receivable                                                    656,360                  413,608
        Inventories                                                                   5,358,696                5,353,696
        Prepaid expenses and other                                                      737,578                  824,720
                                                                                   ------------             ------------

Total current assets                                                                 25,488,095               26,592,585

Long term investments                                                                 1,706,961                1,712,790
Property and equipment, net                                                           3,353,939                3,232,712
Other assets, net                                                                       898,609                  845,668
                                                                                   ------------             ------------

TOTAL ASSETS                                                                       $ 31,447,604             $ 32,383,755
                                                                                   ============             ============

LIABILITIES AND STOCKHOLDERS' EQUITY Current liabilities:

        Accounts payable                                                           $    802,825             $  1,129,470
        Accrued expenses                                                              1,853,890                2,084,490
        Accrued research contracts                                                      331,692                  485,470
        Accrued compensation                                                            162,999                  207,558
        Accrued clinical trial costs                                                  1,532,124                2,085,011
                                                                                   ------------             ------------

        Total current liabilities                                                     4,683,530                5,991,999

Stockholders' equity:
        Common stock                                                                     95,756                   95,536
        Additional paid-in capital                                                   74,224,279               73,967,823
        Treasury stock (75,000 shares at cost)                                       (1,448,950)              (1,448,950)
        Accumulated other comprehensive loss                                            (56,434)                 (54,839)
        Accumulated deficit                                                         (46,050,577)             (46,167,814)
                                                                                   ------------             ------------

        Total stockholders' equity                                                   26,764,074               26,391,756
                                                                                   ------------             ------------

        TOTAL LIABILITIES AND STOCKHOLDERS EQUITY                                  $ 31,447,604             $ 32,383,755
                                                                                   ============             ============
</TABLE>








See notes to consolidated financial statements



                                       1


<PAGE>   4


                         GLIATECH INC. AND SUBSIDIARIES

                      CONSOLIDATED STATEMENTS OF OPERATIONS
                                   (unaudited)
<TABLE>
<CAPTION>


                                                                           THREE MONTHS ENDED
                                                                                 MARCH 31
                                                                   --------------------------------------
                                                                       2000                      1999
                                                                   -----------                -----------


REVENUES
<S>                                                                <C>                        <C>
Product sales                                                      $ 6,831,536                $ 7,756,270
Research contracts and licensing fees                                                             342,796
Government grants                                                      242,752                    185,683
                                                                   -----------                -----------
          Total revenues                                             7,074,288                  8,284,749

OPERATING COSTS AND EXPENSES

Cost of products sold                                                1,202,134                  1,147,130
Research and development                                             2,572,916                  3,940,369
Selling, general and administrative                                  3,452,239                  2,976,276
                                                                   -----------                -----------
          Total operating costs and expenses                         7,227,289                  8,063,775
                                                                   -----------                -----------
Operating (loss) income                                               (153,001)                   220,974
Interest income, net                                                   270,238                    253,268
                                                                   -----------                -----------
NET INCOME                                                         $   117,237                $   474,242
                                                                   ===========                ===========

Earnings per share

          Basic                                                    $      0.01                $      0.05
          Diluted                                                  $      0.01                $      0.05
                                                                   ===========                ===========

Average shares outstanding

          Basic                                                      9,489,341                  9,429,875
          Diluted                                                    9,698,465                 10,154,459
                                                                   ===========                ===========

</TABLE>







See notes to consolidated financial statements.

                                        2


<PAGE>   5

<TABLE>
<CAPTION>

                                                   GLIATECH INC. AND SUBSIDIARIES

                                                CONSOLIDATED STATEMENTS OF CASH FLOWS
                                                             (unaudited)



                                                                                                         THREE MONTHS ENDED
                                                                                                              MARCH 31,
                                                                                                      2000                  1999
                                                                                                  -----------           -----------

Operating activities

<S>                                                                                               <C>                   <C>
Net income                                                                                        $   117,237           $   474,242
Adjustments to reconcile net loss to net cash used in (provided by)
  operating activities:
        Depreciation and amortization                                                                 159,049               125,467
        Patent cost write-off                                                                                               178,122
        Provision (credit) for losses on accounts receivable                                           16,666               (52,396)
        Compensation from issuance of stock and stock options                                          52,313               176,600
        Changes in operating assets and liabilities:
            Accounts receivable                                                                    (2,226,203)             (455,540)
            Inventories                                                                                (5,000)             (522,018)
            Government grants receivable and other assets                                            (155,610)              534,921
            Accounts payable and other accrued expenses                                              (601,808)             (359,555)
            Deferred contract research revenue                                                                             (342,796)
            Other liabilities                                                                        (706,665)              486,131
                                                                                                  -----------           -----------
Net cash used in (provided by) operating activities                                                (3,350,021)              243,178
INVESTING ACTIVITIES

Sale (purchase) of investments, net                                                                 7,684,311              (974,318)
Payment for patent rights and trademarks                                                              (57,304)              (71,453)
Purchase of property and equipment                                                                   (275,909)             (627,656)
                                                                                                  -----------           -----------
Net cash provided by (used in)  investing activities                                                7,351,098            (1,673,427)
FINANCING ACTIVITIES

Proceeds from exercise of stock options                                                               204,363               252,417
                                                                                                  -----------           -----------
Net cash provided by financing activities                                                             204,363               252,417
                                                                                                  -----------           -----------

Increase/(decrease) in cash and cash equivalents                                                    4,205,440            (1,177,832)
Cash and cash equivalents at beginning of period                                                    3,350,245             4,731,814
                                                                                                  -----------           -----------
CASH AND CASH EQUIVALENTS AT END OF PERIOD                                                        $ 7,555,685           $ 3,553,982
                                                                                                  ===========           ===========


</TABLE>









See notes to consolidated financial statements



                                        3

<PAGE>   6






                         GLIATECH INC. AND SUBSIDIARIES

                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
                                   (unaudited)

Note 1.   Basis of Presentation

The accompanying unaudited consolidated financial statements have been prepared
in accordance with generally accepted accounting principles for interim
financial information and with the instructions to Form 10-Q and Article 10 of
Regulation S-X. Accordingly, they do not include all of the information and
footnotes required by generally accepted accounting principles for complete
financial statements. In the opinion of management, all adjustments (consisting
of normal recurring accruals) considered necessary for a fair presentation have
been included. Operating results for the three month period ended March 31, 2000
are not necessarily indicative of the results that may be expected for the year
ending December 31, 2000. These financial statements should be read in
conjunction with the consolidated financial statements and footnotes thereto
included in the Annual Report on Form 10-K of Gliatech Inc. for the fiscal year
ended December 31, 1999 filed with the Securities and Exchange Commission.

Note 2.  Inventories

Inventories consist of:
                                             March 30,             December 31,
                                               2000                     1999
                                            -----------------------------------

                   Raw material             $4,154,195             $4,549,976
                   Work in process           1,010,307                205,007
                   Finished goods              194,194                598,713
                                            ----------             ----------
                                            $5,358,696             $5,353,696
                                            ==========             ==========




Note 3.   Business Segment

The Company operates in one business segment. The Company is engaged in the
discovery and development of biosurgical and therapeutic products to improve
surgical outcomes and to treat neurological disorders. The Company's principal
products are the ADCON(R) family of products, which are medical devices designed
to inhibit excess postsurgical scarring and adhesion following surgery. The
Company sells ADCON(R) products through independent medical device distributors
in approximately 30 countries outside the United States and directly to
hospitals in the United States. The Company does not have foreign facilities and
therefore does not measure operating profit or loss from foreign sales.






                                       4
<PAGE>   7

Domestic and foreign product sales are as follows:

                                             Three Months Ended
                                                  March 31,
                                 ------------------------------------------
                                    2000                           1999
                                 ----------                     ----------
Domestic product sales           $5,859,340                     $6,831,494
Foreign product sales               972,196                        924,776
                                 ----------                     ----------
Total product sales              $6,831,536                     $7,756,270
                                 ==========                     ==========





Note 4.   Comprehensive Income

The components of comprehensive income are as follows:

                                             Three Months Ended
                                                  March 31,
                                   --------------------------------------
                                      2000                          1999
                                   ----------                    --------
Net income                         $ 117,237                     $474,242
Unrealized loss on investments        (1,595)
                                   ---------                     --------
Total comprehensive income         $ 115,642                     $474,242
                                   =========                     ========


The components of accumulated other comprehensive loss are as follows:

                                            March 30,              December 31,
                                             2000                     1999
                                           --------                ------------
Unrealized loss on investments             $(56,434)               $(54,839)

                                           --------                --------
Accumulated other comprehensive loss       $(56,434)               $(54,839)
                                           =========               =========









                                       5
<PAGE>   8

Note 5.   Earnings Per Share Calculation

The following table sets forth the computation of basic and diluted earnings per
share
<TABLE>
<CAPTION>

                                                                          Three Months Ended
                                                                               March 31,
                                                                    2000                        1999
                                                                  ----------                -----------



Basic Earnings Per Share Computation
------------------------------------

<S>                                                               <C>                       <C>
Net Income                                                        $  117,237                $   474,242
                                                                  ==========                ===========

Average Common Shares outstanding                                  9,489,341                  9,429,875
                                                                  ==========                ===========

Basic Earnings Per Share                                          $      .01                $       .05
                                                                  ==========                ===========


Diluted Earnings Per Share Computation
--------------------------------------

Net Income                                                        $  117,237                $   474,242
                                                                  ==========                ===========

Basic Shares Outstanding                                           9,489,341                  9,429,875

Stock Options Calculated Under the Treasury
Stock Method                                                         209,124                    724,585
                                                                  ----------                -----------

Total Shares                                                       9,698,465                 10,154,459
                                                                  ==========                ===========

Diluted Earnings Per Share                                        $      .01                $       .05
                                                                  ==========                ===========

</TABLE>



                                       6






<PAGE>   9




ITEM 2               MANAGEMENT'S DISCUSSION AND ANALYSIS
                OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

OVERVIEW

The Company is engaged in the discovery and development of biosurgical and
therapeutic products to improve surgical outcomes and to treat neurological
disorders. The biosurgical products include the ADCON family of products, which
are proprietary, resorbable, carbohydrate polymer medical devices designed to
inhibit surgical scarring and adhesions. The Company is also pursuing the
development of other biosurgical products and small molecule drug candidates for
the treatment of several neurological disorders, including Attention Deficit
Hyperactive Disorder ("ADHD"), sleep disorders, anxiety, schizophrenia and
Alzheimer Disease ("AD"). The Company anticipates that a significant portion of
revenue from product sales will be derived from its ADCON family of products,
primarily ADCON-L. Based on European pivotal clinical studies and other
compliance efforts and submission of data, the Company obtained regulatory
clearance to affix CE Marking on ADCON-L and ADCON-T/N in August 1995 and
January 1996, respectively, thereby allowing ADCON-L and ADCON-T/N to be
marketed in the 19 European countries which recognize CE Marking for lumbar disc
surgery and tendon and peripheral nerve surgeries, respectively. The Company is
currently marketing ADCON-L and ADCON-T/N through independent medical device
distributors in approximately 30 countries outside the United States, including
the major countries in the European Union pursuant to its CE Marking. The
Company also commenced sales of ADCON-L in the United States in June 1998. In
September 1999, the Food and Drug Administration ("FDA") issued a warning letter
to European Medical Contract Manufacturing ("EMCM"), the Company's third party
manufacturing contractor located in the Netherlands, which led to an import ban
on all ADCON-L shipments to the United States. After a successful re-inspection
of EMCM facilities, the import ban was lifted in December 1999 and the Company
resumed shipments of ADCON-L to the United States in January 2000. In addition,
the Company signed a development and exclusive license agreement in December
1996 with Chugai for the sale of ADCON-L and ADCON-T/N in Japan.

In October 1994, the Company entered into a strategic alliance with Janssen to
collaborate on the discovery and development of therapeutic models to treat AD.
In May 1999, Janssen ceased funding this endeavor. The Company believes that
Janssen does not intend to select a lead compound from the identified compounds
or pursue clinical trials relating to any such compound. The Company is in
discussion with Janssen to transfer development rights of these compounds to the
Company. There can be no assurance that the Company will be successful in
obtaining such development rights from Janssen or, if the Company is successful,
that such rights will be obtained on favorable terms. In addition, the Company
receives revenues from various government grants awarded to the Company.



                                       7
<PAGE>   10

RESULTS OF OPERATIONS

For the three month period ended March 31, 2000 and 1999.

REVENUES

Total revenues decreased by 14.6% to $7.1 million in the first quarter of 2000
from $8.3 million in the first quarter of 1999. The decrease in total revenues
is primarily the result of a decrease in product sales, which decreased to $6.8
million in the first quarter of 2000 from $7.8 million in the first quarter of
1999. This decrease in sales resulted primarily from the unavailability of
ADCON(R)-L for sale in the United States until the end of January 2000. The
decrease in total revenues was also due to no research contract revenues during
this period because, as of June 1999, Janssen was no longer funding the
collaboration efforts with the Company.

The decrease in revenues was slightly offset by the Company's government-funded
grant revenues, which increased to $242,752 in the first quarter of 2000 from
$185,683 in the first quarter of 1999. This increase is the result of the
Company having two Phase II Small Business Innovation Research ("SBIR") grants.

OPERATING COSTS AND EXPENSES

Total operating expenses decreased by 10.4% to $7.2 million in the first quarter
of 2000, compared to $8.1 million in the first quarter of 1999. Cost of products
sold increased to $1.2 million in the first quarter of 2000 compared to $1.1
million in the first quarter of 1999, and increased, as a percentage of product
sales, in the first quarter of 2000 to 17.6% from 14.8% in the first quarter of
1999. The percentage increase in the first quarter of 2000 is primarily due to
startup costs associated with the Company's new manufacturing plant in Solon,
Ohio, which is currently undergoing validation testing.

Research and development expenses decreased by 34.7 % to $2.6 million in the
first quarter of 2000 from $3.9 million in the first quarter of 1999. This
decrease was primarily in clinical development costs due to: i) the ADCON(R)-P
pivotal trial nearing completion in patient enrollment resulting in a lesser
cost incurred during the first quarter of 2000 versus the first quarter of 1999
and ii) the pilot studies for ADCON(R)-A (for inhibition of postsurgical
scarring and adhesion following abdominal or colorectal surgeries) and
ADCON(R)-L gel (for inhibition of postsurgical scarring and adhesion following
breast augmentation surgery) were fully enrolled and expensed by the end of
fiscal 1999.




                                       8
<PAGE>   11

Selling, general and administrative expenses increased 16.0% to $3.5 million in
the first quarter of 2000 compared to $3.0 million in the first quarter of 1999.
This increase was primarily due to an increase in the sales and marketing
expenses incurred in connection with the successful relaunch of ADCON(R)-L in
the U.S.

INTEREST INCOME

Interest income, net increased by 6.7% to $270,238 in the first quarter of 2000
from $253,268 in the first quarter of 1999.


NET INCOME

Gliatech's net income decreased by 75.3% to $117,237 in the first quarter of
2000, compared to a net income of $474,242 in the first quarter of 1999. The
decrease in net income is primarily from the unavailability of ADCON(R)-L for
sales in the United States until the end of January 2000. The basic and diluted
earnings per common share was $0.01 in the first quarter of 2000, compared to a
net income per common share of $0.05 in the first quarter of 1999.

CONSOLIDATED BALANCE SHEETS

Accounts receivable increased by $2.2 million to $3.1 million at March 31,
2000, compared to $.9 million at December 31, 1999. This increase was due to
the Company resuming shipments of ADCON(R)-L in the United States in
January 2000.

LIQUIDITY AND CAPITAL RESOURCES

In order to preserve principal and maintain liquidity, the Company's funds are
invested primarily in commercial paper and other short-term investments. As of
March 31, 2000 and December 31, 1999, the Company's cash and cash equivalents,
short-term and long-term investments totaled $17.3 million and $20.8 million,
respectively. The Company expects that its existing capital resources, interest
earned thereon, and product sales will enable the Company to maintain its
current and planned operations for the foreseeable future.

Prior to the commercialization of ADCON-L in the United States, the Company
historically financed its operations primarily through the private placement and
public offering of its equity securities, research contract licensing fees, and,
to a lesser extent, through federally sponsored research grants. The Company
also has established a $1.5 million line of credit with a bank. As of March 31,
2000, the Company had no borrowings against the line of credit.

The Company may need to raise substantial additional capital to fund its
operations. The Company's future capital requirements will depend on, and could
increase as a result of many factors, including,





                                       9
<PAGE>   12

but not limited to, the cost for commercialization of ADCON-L, the
commercialization success of its ADCON family of products, the progress of the
Company's research and development, including the costs related to its Cognition
Modulation, Perceptin, AD, schizophrenia and other neurological disorders
programs, the scope, timing and results of preclinical studies and clinical
trials, the cost and timing of obtaining regulatory approvals, the Company's
success in obtaining the strategic alliances required to fund certain of its
programs, the rate of technological advances, determinations as to the
commercial potential of certain of the Company's product candidates, the status
of competitive products and the establishment of additional manufacturing
capacity.

In the second quarter of 1999 the Company was awarded a third Phase II SBIR
Program grant from the National Cancer Institute ("NCI"), a division of the NIH,
for the research of inhibition of postoperative gynecological adhesions. In
September 1998, the Company was awarded a Phase II SBIR Program grant from the
NINDS for research evaluating H (3) agonists. Each of these Phase II grants has
a two-year term and each may provide as much as approximately $750,000 in
funding. In February 1997 the Company was awarded a two-year Phase II SBIR
Program grant from NINDS for research evaluating histamine H (3) receptor
antagonists to treat ADHD, which may provide as much as $750,000 in funding. If
the Company is successful in other Phase I research, additional Phase II awards
may be sought for funding to aid in further development of pharmaceutical
compounds, however, there is no assurance that such Phase I research will be
successful or that additional funding will be obtained.

While the Company had a positive cash flow for the first quarter of 2000 it may
not be indicative of future quarters due to the substantial costs for
commercialization of ADCON-L, additional research and development costs for its
other biosurgical products and costs related to its neurosurgical disorders
programs, preclinical testing, clinical trials and operating expenses associated
with supporting such activities. The Company's ability to generate a positive
cash flow from operations is dependent upon several factors, including the
timing and content of decisions by the FDA.

The Company from time to time is involved in various stages of discussion or
negotiation regarding acquisitions or mergers and from time to time other
strategic alternatives. As of the date hereof, the Company has not entered into
any definitive agreement with respect to any such transaction or other strategic
alternative.


EURO CONVERSION.

On January 1, 1999, eleven of the fifteen countries (the "Participating
Countries") that are members of the European Union established a new uniform
currency known as the "Euro." The currencies existing prior to such date in the
Participating Countries will be phased out during the transition period
commencing January 1, 1999 and ending January 1, 2002. During such transition
period both the Euro and the existing currencies will be available in the
Participating Countries. Although certain of the Company's products are being
sold in the Participating Countries through independent distributors, the
Company receives revenues from such sales in U.S. dollars. As a result, the





                                       10
<PAGE>   13

Company does not anticipate that the introduction and use of the Euro will
materially affect the Company's business, prospects, results of operations or
financial condition

FORWARD-LOOKING STATEMENTS. Certain statements in this Quarterly Report on Form
10-Q constitute "forward-looking statements." When used in this Form 10-Q, the
words "believes," "anticipates," "expects," "intends" and other predictive,
interpretive and similar expressions are intended to identify such
forward-looking statements. Such forward-looking statements involve known and
unknown risks, uncertainties and other factors that may cause the actual results
of the Company to be different from expectations expressed or implied by such
forward-looking statements. Such factors included, but are not limited to,
commercial uncertainty of market acceptance of the Company's ADCON(R) family of
products, including the timing and content of decisions made by the FDA,
commercial uncertainty of the market acceptance of the Company's ADCON(R) family
of products, delays in product development of additional ADCON(R) products,
uncertainty of outcomes of future FDA audits and inspections, uncertainty due to
the early stage of development for the neurological disorder programs, the
possible need for additional funding, the ability the Company to establish and
maintain collaborative arrangements with others, the potential market size of
ADCON(R) products, the ability to extend research collaborations, uncertainties
relating to the integration and completion of any strategic alternative, the
productivity of distributors of the ADCON(R) products, the uncertainty of
shortages of supply of ADCON(R) products from the Company's sole manufacturer,
the ability of the Company to commence manufacturing of its ADCON(R) products at
its manufacturing facility located in the United States, the lack of supply of
raw materials for the Company's products, uncertainty of future profitability,
uncertainties related to the Company's proprietary rights in its products, the
loss of key management, and personnel and technological change. These statements
are based on certain assumptions and analysis made by the Company in light of
its experience and its perception of historical trends, current conditions,
expected future developments and other factors it believes are appropriate in
the circumstances. Such statements are subject to a number of other assumptions,
risks, uncertainties, general economic and business conditions, and the business
opportunities (or lack thereof) that may be presented to and pursued by the
Company. Prospective investors are cautioned that any such statements are not
guarantees of future performance and that actual results or developments may
differ materially from those projected in the forward-looking statements.







                                       11
<PAGE>   14



ITEM 3                QUANTITATIVE AND QUALITATIVE DISCLOSURES
                                ABOUT MARKET RISK

The Company does not enter into derivative financial instruments. The Company
primarily invests in commercial paper and corporate bonds that have short-term
maturities. The Company has no outstanding debt. Exposure to foreign currency
has been minimal because the Company's foreign product sales are in U.S.
currency. As a result, the Company believes that its market risk exposure is not
material to the Company's financial position, liquidity or results of
operations.








                                       12

<PAGE>   15




                                     PART II

                                OTHER INFORMATION

ITEM 1: LEGAL PROCEEDINGS

         On March 17, 2000, Derrick McKinley, M.D. filed a lawsuit against the
         Company and certain of its officers in the Court of Common Pleas in
         Cuyahoga County, Ohio alleging wrongful and tortious discharge and
         tortious interference with employment. Such claims arose from the
         termination of his employment with the Company. The complaint seeks
         unspecific monetary damages in an amount in excess of $25,000 in the
         form of compensatory, consequential and punitive damages. The Company
         believes this suit is without merit and intends to vigorously defend
         this suit.

ITEM 6: EXHIBITS AND REPORTS ON FORM 8-K

(a)      Exhibits

         10.1     Amended Form of U.S. Manufacturer's Representative Agreement

         27.1     Financial data schedule

(b)      Reports on Form 8-K

         The Company did not file any Current Reports on Form 8-K for the period
         covered by this Quarterly Report on Form 10-Q







                                       13
<PAGE>   16


                                   SIGNATURES

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

Date: May 15, 2000        GLIATECH INC.




                          By:   /s/Rodney E. Dausch
                              ------------------------------------------------
                              Rodney E. Dausch
                              Executive Vice President, Chief Financial Officer
                                  and Secretary
                              (Duly Authorized Officer and Principal
                                  Financial and Accounting Officer)









                                       14

<PAGE>   17




                                  EXHIBIT INDEX

Exhibit No.        Description of Exhibit                      Page Number
-----------        ----------------------                      -----------

10.1               Amended Form of U.S. Manufacturer's              16
                    Representative Agreement

27.1               Financial Data Schedule                          17










                                       15