Exhibit 10.56

                     AMENDMENT NO. 1 TO NOVA BUILDING LEASE
                           DATED AS OF MARCH 28, 2001
                                 BY AND BETWEEN
                SAMUEL C. POWELL AND KAREN G. POWELL ("LANDLORD")
                                       AND
                        MEDTOX SCIENTIFIC, INC ("TENANT")


     THIS  AMENDMENT  is made and entered into  effective  the 1st day of April,
     2001 by and  between  SAMUEL  C.  POWELL  and KAREN G.  POWELL,  individual
     residents  of  the  State  of  North  Carolina   (hereinafter  referred  to
     collectively  as  "Landlord"),  and  MEDTOX  SCIENTIFIC,  INC.,  a Delaware
     corporation (hereinafter referred to as "Tenant").

                                    RECITALS

     WHEREAS,  Landlord and Tenant  entered Lease of property  commonly known as
     the "Nova Building" on March 28, 2001; and

     WHEREAS,  said Lease  provided in  Paragraph  4.03 that Tenant may elect to
     have Landlord pay up to $600,000 for  improvements to the Demised  Premises
     and that to the extent that  Landlord  should  advance  such funds,  Tenant
     would repay such advance by an increase in the Monthly Rental due under the
     Lease. The increase in the Monthly Rental shall be an amount  sufficient to
     amortize the  principle  of such an advance,  on a monthly  basis,  over 10
     years at annual interest rate of 9.5%; and

     WHEREAS,  Landlord  has to  date  advanced  $300,000  to  Tenant  for  such
     improvements by a virtue of a Promissory Note dated February 2001 a copy of
     which is attached hereto as Exhibit "A"; and

     WHEREAS,  the Parties  now wish to amend the Lease to increase  the Monthly
     Rental by an amount  sufficient  to amortize  the  $300,000  advance as set
     forth above and to cancel the Promissory Note.

     NOW,  THEREFORE,  in  consideration  of the mutual covenants and agreements
     contained  herein,  Landlord and Tenant  hereby agree to amend the Lease as
     follows:

     1. Except as otherwise  expressly  provided for herein,  capitalized  terms
     used herein shall have the meaning ascribed to such terms in the Lease.

     2. Except as specifically  provided for in this Amendment,  the Lease shall
     remain in full force and effect in accordance  with its original  terms and
     conditions.

     3.  Effective as of April 1, 2001 the Monthly  Rental shall be increased by
     $3,881.93 which is the amount  sufficient to amortize the $300,000 advanced
     by Landlord  to Tenant to fund  improvements  on the  Premises on a monthly
     basis over a 10 year term.  Any unpaid  balance  remaining  on the $300,000
     advance upon the expiration of the Initial Term or early termination of the

<PAGE>

     Lease shall be paid within 7 days following such  expiration or termination
     as provided in Paragraph 4.03 of the Lease.

     4.  Effective as of the date hereof the  Promissory  Note shall be null and
     void and of no effect.

     5. This  Amendment  may be executed in a number of identical  counterparts,
     and in telecopy or facsimile  transmission shall be binding on the party or
     parties  whose  signatures  appear  thereon.  If so executed,  each of such
     counterparts  is to be deemed an original  for all  purposes,  and all such
     counterparts shall, collectively,  constitute one amendment , but in making
     proof of this  Amendment,  it shall not be  necessary to produce or account
     for more than one such counterpart.

DATED EFFECTIVE: April 1, 2001

AS TO Landlord:                            LANDLORD:

Signed, sealed and delivered in the
presence of:
                                           ____________________________(SEAL)
                                           Samuel C. Powell

________________________________
[Unofficial Witness]
                                           ____________________________(SEAL)
________________________________           Karen G. Powell
[Witness] [Notary Public]

(Affix seal and date of expiration
of commission)



AS TO Tenant:                              TENANT:

Signed, sealed and delivered in the
presence of:                               MEDTOX SCIENTIFIC, INC.,
                                           a Delaware corporation

                                           By:______________________________
________________________________                 Name: James Lockhart
[Unofficial Witness]                             Title: VP Fin. and Admin.

________________________________
[Witness] [Notary Public]

(Affix seal and date of expiration of
commission)

<PAGE>

                                   EXHIBIT "A"

                                 PROMISSORY NOTE



$ 300,000                                                  St Paul, Minnesota
"LOAN AMOUNT"                                                 February 2001


     FOR VALUE RECEIVED,  the undersigned,  METOX  Diagnostics,  Inc. and MEDTOX
Scientific, Inc.(herein after collectively the "Borrower") do hereby jointly and
severely  promise  to pay to the  order of  Samuel  C.  Powell  ("Powell  "), an
individual  residing in the state of North Carolina,  the entire LOAN AMOUNT and
all  accrued  interest  thereon.  Payment  of the LOAN  AMOUNT  and all  accrued
interest  thereon  shall be made at such  place as the  holder  of this Note may
designate from time to time.


     Interest shall be computed on the basis of actual days elapsed in a year of
three hundred sixty (365) days and shall be paid monthly on the unpaid principal
balance hereof at an annual rate of nine and one-half percent ( 9.5%).


     Interest  only shall be payable  monthly on this NOTE until the  earlier of
March 31, 2001 or the execution of a 10 year lease between  MEDTOX  Diagnostics,
Inc and Powell for the  facility  located at 1238  Anthony  Road in  Burlington,
North Carolina. If no such lease has been executed by March 31, 2001, the entire
LOAN  AMOUNT and all  accrued  and unpaid  interest  shall  immediately  due and
payable.  If such  lease  has been  executed  on or before  March 31,  2001 then
commencing  with the first  month of such lease the entire  LOAN  AMOUNT and all
accrued interest shall be paid in 120 equal monthly  installments as an addition
to the lease payments made each month by MEDTOX Diagnostics, Inc to Powell under
said lease.  All payments  hereunder shall first be applied to accrued  interest
and the remainder shall be applied to reduction of principal.  The  indebtedness
evidenced  by  this  Note  may be  prepaid  at any  time  without  penalty.  Any
prepayments  shall be  applied  first to  accrued  interest  and the  balance to
principal,  and  shall  not  postpone  the due  date of any  subsequent  monthly
installments or reduce the required amount thereof.

     In the  event  the  principal  of or  interest  on this  Note,  or any part
thereof,  is not paid when due, at maturity  or upon  acceleration,  or Borrower
otherwise defaults in its obligations under this Note and this Note is placed in
the hands of an attorney for collection,  Borrower,  its successors and assigns,
will repay on demand all costs and expenses of collection so incurred, including
reasonable  attorneys' fees, whether or not suit or legal proceeding is actually
commenced for the collection thereof.
<PAGE>


     Presentment,  notice of  dishonor,  and  protest  are hereby  waived by the
Borrower.  This Note may not be modified  orally,  but only by an  agreement  in
writing and signed by the party against whom enforcement of any waiver,  change,
modification or discharge is sought.

("BORROWER")

MEDTOX Diagnostics, Inc.


BY: ____________________

 ITS: ______________

And


MEDTOX Scientific, Inc.

BY: ____________________

 ITS: ______________