WAC 458-20-18801 (Rule 18801) is the administrative rule that explains retail sales
tax and use tax exemptions for medical products, including the exemption under RCW 82.08.925.
Rule 18801(403) states as follows:
(e) Dietary supplements (also known as nutrition products) with a prescription are
exempt from retail sales and use taxes. Sales of dietary supplements not covered by either
of the retail sales tax or use tax exemptions for "food and food ingredients" are generally
subject to retail sales tax or use tax. See RCW 82.08.0293 and 82.12.0293. However, RCW
82.08.925 and 82.12.925 provide specific retail sales tax and use tax exemptions for sales
of "dietary supplements" for human use, pursuant to a prescription. A "dietary supplement"
is any product, other than tobacco, intended to supplement the diet, and that satisfies all
three of the criteria listed in (e)(i) through (iii) of this subsection.
(i) Contains one or more of the following dietary ingredients:
(A) A vitamin;
(B) A mineral;
(C) An herb or other botanical;
(D) An amino acid;
(E) A dietary substance for use by humans to supplement the diet by increasing the total
dietary intake; or
(F) A concentrate, metabolite, constituent, extract, or combination of any ingredient
described in this subsection.
(ii) Is intended for ingestion in tablet, capsule, powder, softgel, gelcap, or liquid form, or
if not intended for ingestion in such form, is not represented as conventional food and is
not represented for use as a sole item of a meal or of the diet; and
(iii) Is required to be labeled as a dietary supplement, identifiable by the "supplement facts"
box found on the label as required pursuant to 21 C.F.R. Sec. 101.36, as amended or
renumbered as of January 1, 2003. See RCW 82.08.0293.
(Emphasis in original.) Rule 18801(402) explains that most exemptions for medical products
require that the item is purchased under authority of a prescription, which it defines as follows:
(a) What is a prescription? A “prescription” is an order, formula, or recipe issued in any
form of oral, written, electronic, or other means of transmission by a duly licensed
practitioner authorized by the laws of this state to prescribe.
Thus, the Washington State legislature has provided an exemption from the retail sales tax for
sales of dietary supplements for human use but such sales are only exempt under RCW 82.08.925
if the supplements are dispensed or to be dispensed to patients, pursuant to a prescription. See also
RCW 82.08.0281(4). Exemptions and deductions are narrowly construed. Budget Rent-a-Car,
Inc. v. Dep’t of Revenue, 81 Wn.2d 171, 500 P.2d 764 (1972); Det. No. 03-0252, 23 WTD 223
(2004). The Department, as an administrative agency implementing the taxing statutes of this
Pursuant to RCW 82.08.0293 (1) Food and Food ingredients are defined as “… substances, whether in liquid,
concentrated, solid, frozen, dried, or dehydrated form, that are sold for ingestion or chewing by humans and are
consumed for their taste or nutritional value. (2) The exemption of "food and food ingredients" provided for in
subsection (1) of this section does not apply to … dietary supplements. See also, WAC 458-20-244, the administrative
rule that implements this statute.