<PAGE>

                                SUPPLEMENTAL INDENTURE
                                ----------------------

     SUPPLEMENTAL INDENTURE (this "Supplemental Indenture"), dated as of 
December 11, 1998, among American Ingredients, Inc. (the "New Subsidiary 
Guarantor"), and indirect subsidiary of Global Health Sciences, Inc., a 
California corporation (the "Company"), the Company, the Subsidiary 
Guarantors (the "Existing Subsidiary Guarantors") under the Indenture 
referred to below, and Chase Manhattan Bank and Trust Company, National 
Association, a national banking association, as trustee under the Indenture 
referred to below (the "Trustee").

                                     W I T N E S S E T H:
                                     - - - - - - - - - - 

     WHEREAS the Company has heretofore executed and delivered to the 
Trustee an Indenture (as such may be amended from time to time, the 
"Indenture"). dated as of April 23, 1998, providing for the issuance of an 
aggregate principal amount of up to $325,000 of 11% Senior Notes due 2008 
(the "Notes");

     WHEREAS Section 4.18 of the Indenture provides that under certain 
circumstances the Company is required to cause the New Subsidiary Guarantor 
to execute and deliver to the Trustee a supplemental indenture pursuant to 
which the New Subsidiary Guarantor shall unconditionally guarantee all of the 
Company's obligations under the Notes and the Indenture pursuant to a 
Guarantee on the terms and conditions set forth herein; and

     WHEREAS pursuant to Section 8.01 of the Indenture, the Trustee, the 
Company and Existing Subsidiary Guarantors are authorized to execute and 
deliver this Supplemental Indenture;

     NOW THEREFORE, in consideration of the foregoing and for other good and 
valuable consideration, the receipt of which is hereby acknowledged, the New 
Subsidiary Guarantor, the Company, the Existing Subsidiary Guarantors and the 
Trustee mutually covenant and agree for the equal and ratable benefit of the 
Holders of the Notes as follows:

     1.  Definitions. (a) Capitalized terms used herein without definition 
shall have the meanings assigned to them in the Indenture.

     (b) For all purposes of this Supplemental Indenture, except as otherwise 
herein expressly provided or unless the context otherwise requires. (i) the 
terms and expressions used herein shall have the same meanings as 
corresponding terms and expressions used in the Indenture; and (ii) the 
words "herein", "hereof" and

<PAGE>

"hereby" and other words of similar import used in this Supplemental 
Indenture refer to this Supplemental Indenture as a whole and not to any 
particular section hereof.

     2.  Agreement to Guarantee. The New Subsidiary Guarantor hereby agrees, 
jointly and severally with all other Subsidiary Guarantors, to guarantee the 
Company's obligations under the Notes and the Indenture on the terms and 
subject to the conditions set forth in Article 10 of the Indenture 
(including, without limitation, the subordination provisions thereof) and to 
be bound by all other applicable provisions of the Indenture. From and after 
the date hereof, the New Subsidiary Guarantor shall be a Subsidiary Guarantor 
for all purposes under the Indenture and the Notes.

     3.  Execution of New Guarantee. To evidence the Guarantee set forth in 
this Supplemental Indenture, the New Subsidiary Guarantor hereby agrees that a 
notation of such Guarantee in accordance with Section 10.09 of the Indenture 
will be placed on the Notes. The Trustee is hereby authorized and directed, 
with no further action by the Company, the New Subsidiary Guarantor or the 
other Subsidiary Guarantors, to replace the Guarantee currently attached to 
the Notes with the Guarantee executed in connection herewith.

     4.  Ratification of Indenture: Supplemental Indentures part of 
Indenture. Except as expressly amended hereby, the Indenture is in all 
respects ratified and confirmed and all the terms, conditions and provisions 
thereof shall remain in full force and effect. This Supplemental Indenture 
shall form a part of the Indenture for all purposes, and every holder of 
Notes heretofore or hereafter authenticated and delivered shall be bound 
hereby.

     5.  Governing Law. THIS SUPPLEMENTAL INDENTURE SHALL BE GOVERNED BY, AND 
CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK BUT WITHOUT 
GIVING EFFECT TO APPLICABLE PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT THAT 
THE APPLICATION OF THE LAWS OF ANOTHER JURISDICTION WOULD BE REQUIRED THEREBY.

     6.  Trustee Makes No Representation. The Trustee makes no representation 
as to the validity or sufficiency of this Supplemental Indenture.

     7.  Counterparts. The parties may sign any number of copies of this 
Supplemental Indenture. Each signed copy shall be an original, but all of 
them together represent the same agreement.

     8.  Effect of Headings. The Section headings herein are for convenience 
only and shall not affect the construction thereof.

<PAGE>

     IN WITNESS WHEREOF, the parties hereto have caused this Supplemental 
Indenture to be duly executed as of the date first above written.


                                            AMERICAN INGREDIENTS INC.


                                            By:  
                                            --------------------------
                                            Name:
                                            Title:


                                            GLOBAL HEALTH SCIENCES, INC.:


                                            By:  
                                            --------------------------
                                            Name:
                                            Title:


                                            GLOBAL HEALTH SUB, INC.:


                                            By:  
                                            --------------------------
                                            Name:
                                            Title:


                                            D&F INDUSTRIES, INC.:


                                            By:  
                                            --------------------------
                                            Name:
                                            Title:


                                            RAVEN INDUSTRIES, INC.:


                                            By:  
                                            --------------------------
                                            Name:
                                            Title:


<PAGE>

                                            DYNAMIC PRODUCTS, INC.:


                                            By:  
                                            --------------------------
                                            Name:
                                            Title:


                                            WEST COAST SALES:


                                            By:  
                                            --------------------------
                                            Name:
                                            Title:


                                            CHASE MANHATTAN BANK AND
                                            TRUST COMPANY
                                            NATIONAL ASSOCIATION:


                                            By:  
                                            --------------------------
                                            Name:
                                            Title: