FOURTH AMENDMENT TO CREDIT AGREEMENT

Exhibit 10.1

FOURTH AMENDMENT TO CREDIT AGREEMENT

          THIS AMENDMENT TO CREDIT AGREEMENT (this "Amendment") is entered into as of October 29, 2009, by and between MEDTOX SCIENTIFIC, INC., MEDTOX DIAGNOSTICS, INC. and MEDTOX LABORATORIES, INC., each a Delaware corporation (each individually a "Borrower"), and WELLS FARGO BANK, NATIONAL ASSOCIATION ("Bank"). Each reference herein to “Borrower” shall mean each and every party, collectively and individually, defined above as a Borrower.

RECITALS

          WHEREAS, Borrower is currently indebted to Bank pursuant 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 ("Credit Agreement").

          WHEREAS, Bank and Borrower have agreed to certain changes in the terms and conditions set forth in the Credit Agreement and have agreed to amend the Credit Agreement to reflect said changes.

          NOW, THEREFORE, for valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto agree that the Credit Agreement shall be amended as follows:

          1.         Section 1.1 (a) is hereby amended by deleting "November 1, 2009" as the last day on which Bank will make advances under the Line of Credit, and by substituting for said date "August 31, 2011," with such change to be effective upon the execution and delivery to Bank of a promissory note dated as of October 29, 2009, (which promissory note shall replace and be deemed the Line of Credit Note defined in and made pursuant to the Credit Agreement) and all other contracts, instruments and documents required by Bank to evidence such change.

          2.         Section 1.4 (e) is hereby deleted in its entirety, and the following substituted therefor:

                      “(e) Unused Commitment Fee. Borrower shall pay to Bank a fee equal to one quarter of one percent (0.25%) per annum (computed on the basis of a 360-day year, actual days elapsed) on the average daily unused amount of the Line of Credit, which fee shall be calculated on a quarterly basis by Bank and shall be due and payable by Borrower in arrears within ten (1) days after each billing is sent by Bank.”

          3.         Section 4.9 (a) is hereby deleted in its entirety, and the following substituted therefor:

                      “(a) Tangible Net Worth not less than $40,000,000.00 at any time, with “Tangible Net Worth” defined as the aggregate of total stockholders’ equity plus subordinated debtless any intangible assets.”

“(d) Current Ratio not less than 1.3 to 1.0 at each month end, with “Current Ratio” defined as total current assets divided by total current liabilities.”             

          5.         Except as specifically provided herein, all terms and conditions of the Credit Agreement remain in full force and effect, without waiver or modification. All terms defined in the Credit Agreement shall have the same meaning when used in this Amendment. This Amendment and the Credit Agreement shall be read together, as one document.

          6.         Borrower hereby remakes all representations and warranties contained in the Credit Agreement and reaffirms all covenants set forth therein. Borrower further certifies that as of the date of this Amendment there exists no Event of Default as defined in the Credit Agreement, nor any condition, act or event which with the giving of notice or the passage of time or both would constitute any such Event of Default.

          IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be executed as of the day and year first written above.

Title: V.P./CFO __________________

MEDTOX DIAGNOSTICS, INC.

By: /s/ Kevin J. Wiersma ___________

Title: V.P./CFO __________________

MEDTOX LABORATORIES, INC.

By: /s/ Kevin J. Wiersma ___________

Title: V.P./CFO __________________

REVOLVING LINE OF CREDIT NOTE

_____________________

          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 6 ^th and Marquette, Minneapolis, Minnesota 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 Eight Million Dollars ($8,000,000.00), or so much thereof as may be advanced and be outstanding, with interest thereon, to be computed on each advance from the date of its disbursement as set forth herein.

DEFINITIONS:

          As used herein, the following terms shall have the meanings set forth after each, and any other term defined in this Note shall have the meaning set forth at the place defined:

          (a)       "Business Day" means any day except a Saturday, Sunday or any other day on which commercial banks in Minnesota are authorized or required by law to close.

          (b)       "Daily Three Month LIBOR" means, for any day, the rate of interest equal to LIBOR then in effect for delivery for a three (3) month period.

          (c)       "LIBOR" means the rate per annum (rounded upward, if necessary, to the nearest whole 1/8 of 1%) and determined pursuant to the following formula: