Exhibit 10.5

WELLS FARGO TERM NOTE $341,403.42 Minneapolis, Minnesota   December 1, 2005

FOR VALUE RECEIVED, the undersigned MEDTOX SCIENTIFIC, INC., MEDTOX DIAGNOSTICS,
INC. and MEDTOX LABORATORIES, INC. (“Borrower”) promises to pay to the order of
WELLS FARGO BANK, NATIONAL ASSOCIATION (“Bank”) at its office at Minneapolis
RCBO, Sixth and Marquette, Minneapolis, MN 55479, or at such other place as the
holder hereof may designate, in lawful money of the United States of America and
in immediately available funds, the principal sum of $341,403.42, with interest
thereon as set forth herein.

1.    INTEREST:

1.1 Interest. The outstanding principal balance of this Note shall bear interest
(computed on the basis of a 360-day year, actual days elapsed) at a rate per
annum 0.25000% below the Prime Rate in effect from time to time. The “Prime
Rate” is a base rate that Bank from time to time establishes and which serves as
the basis upon which effective rates of interest are calculated for those loans
making reference thereto. Each change in the rate of interest hereunder shall
become effective on the date each Prime Rate change is announced within Bank.

1.2 Payment of Interest. Interest accrued on this Note shall be payable on the
1st day of each month, commencing January 1, 2006.

1.3 Default Interest. From and after the maturity date of this Note, or such
earlier date as all principal owing hereunder becomes due and payable by
acceleration or otherwise, the outstanding principal balance of this Note shall
bear interest until paid in full at an increased rate per annum (computed on the
basis of a 360-day year, actual days elapsed) equal to 4% above the rate of
interest from time to time applicable to this Note.

2.    REPAYMENT AND PREPAYMENT:

2.1 Repayment. Principal shall be payable on the 1st day of each month in
installments of $8,984.30 each, commencing January 1, 2006, and continuing up to
and including January 1, 2009, with a final installment consisting of all
remaining unpaid principal due and payable in full on February 1, 2009.

2.2 Application of Payments. Each payment made on this Note shall be credited
first, to any interest then due and second, to the outstanding principal balance
hereof.

2.3 Prepayment. Borrower may prepay principal on this Note at any time, in any
amount and without penalty. All prepayments of principal shall be applied on the
most remote principal installment or installments then unpaid.

3.     EVENTS OF DEFAULT:

        This Note is made pursuant to and is subject to the terms and conditions
of that certain Credit Agreement between Borrower and Bank dated as of December
1, 2005, as amended from time to time (the “Credit Agreement”). Any default in
the payment or performance of any obligation under this Note, or any defined
event of default under the Credit Agreement, shall constitute an “Event of
Default” under this Note.

4.    MISCELLANEOUS:

4.1 Remedies. Upon the occurrence of any Event of Default, the holder of this
Note, at the holder’s option, may declare all sums of principal and interest
outstanding hereunder to be immediately due and payable without presentment,
demand, notice of nonperformance, notice of protest, protest or notice of
dishonor, all of which are expressly waived by each Borrower, and the
obligation, if any, of the holder to extend any further credit hereunder shall
immediately cease and terminate. Each Borrower shall pay to the holder
immediately upon demand the full amount of all payments, advances, charges,
costs and expenses, including reasonable attorneys’ fees (to include outside
counsel fees and all allocated costs of the holder’s in-house counsel), expended
or incurred by the holder in connection with the enforcement of the holder’s
rights and/or the collection of any amounts which become due to the holder under
this Note, and the prosecution or defense of any action in any way related to
this Note, including without limitation, any action for declaratory relief,
whether incurred at the trial or appellate level, in an arbitration proceeding
or otherwise, and including any of the foregoing incurred in connection with any
bankruptcy proceeding (including without limitation, any adversary proceeding,
contested matter or motion brought by Bank or any other person) relating to any
Borrower or any other person or entity.

4.2 Obligations Joint and Several. Should more than one person or entity sign
this Note as a Borrower, the obligations of each such Borrower shall be joint
and several.

4.3 Governing Law. This Note shall be governed by and construed in accordance
with the laws of the State of Minnesota.

IN WITNESS WHEREOF, the undersigned has executed this Note as of the date first
written above.

MEDTOX SCIENTIFIC, INC.

By: /s/ Kevin J. Wiersma

Title: CFO

MEDTOX DIAGNOSTICS, INC.

By: /s/ Kevin J. Wiersma

Title: CFO

MEDTOX LABORATORIES, INC.

By: /s/ Kevin J. Wiersma

Title: CFO