Illustrative milk thistle and dandelion flowers, not a product photograph or an identification test.
The same plant can show up on a supplement label two ways: a common name like "milk thistle," and a Latin binomial in parentheses, like "Silybum marianum." Neither is decoration. Federal labeling rules say which common names a botanical ingredient can carry and when the Latin name has to appear - and reading the two names correctly keeps you from confusing a plant's name with two other facts on the same panel: its plant part and its preparation. This is a guide to interpreting label names, not a claim about any product.
What the rules actually require
Under 21 CFR 101.4(h), the common or usual name of a botanical dietary ingredient must be consistent with the names standardized in a reference called Herbs of Commerce, which the rule incorporates in its 1992 edition. The listing must be followed by two more statements. First, the part of the plant the ingredient comes from, expressed in English - "flower," not "flos." The plant-part designation is not required for algae. Second, the Latin binomial name, in parentheses - with an exception that matters: the binomial is not required when it is already available in Herbs of Commerce for the common name on the label. So a botanical listed without a Latin name is not automatically mislabeled. The rule also lets a single-ingredient supplement that carries no ingredient list prominently place the binomial, when needed, and plant part on its principal display panel or information panel, or include them in the nutrition label.
Three facts the panel keeps separate
A botanical line can carry up to three different facts, and they answer different questions:
- The name tells you which plant the label declares - as a standardized common name, with the Latin binomial added when the rule requires it or the brand chooses to include it.
- The plant part tells you what was used: seed, root, leaf or flower are different declarations, and two products naming the same plant can use different parts.
- The preparation tells you how it was processed: a powder, or an extract, sometimes with a ratio. An extract ratio is the label's stated relationship between starting material and extract; on its own it does not verify a named constituent's amount, quality or effect.
When a positive identification cannot be made without it, 21 CFR 101.4(h) also requires the designation of the author or authors who published the Latin name.
A Latin binomial does not tell you the part or the preparation, and an extract line does not tell you the Latin name. Read each fact where it sits on the panel.
What a Latin name does and does not establish
NCCIH lists Silybum marianum for milk thistle and Taraxacum officinale for dandelion. These are generic naming examples, not a transcription of a VITAMIZED label. A binomial like Silybum marianum (the binomial associated with milk thistle) or Taraxacum officinale (associated with dandelion) identifies the declared plant in the shared vocabulary of botanical nomenclature. That is a naming function, not a test result. A printed Latin name is not, by itself, evidence of identity testing, quality or any effect - and, because of the Herbs of Commerce exception, its absence is not automatically a problem either.
Read the name the label prints, not the one you expect
The rule ties common or usual label names to a standardized reference. When a label prints a particular botanical name, read it as that product's declaration. Don't swap it for a more familiar synonym, and don't assume it refers to a related plant you had in mind. If the precise identity behind a name matters to your decision, the printed name is the one to raise with the brand or with your clinician.
Keep reading
For the wider label read around these names, see our Milk Thistle and Daily Liver Support Label Guide, and for one botanical walked line by line, the Dandelion Root Supplement Label Guide.
The bottom line
The name - common or Latin - the plant part and the preparation are separate facts on a botanical label. Federal rules decide when each must appear, including the exception that lets a standardized common name stand without its binomial. None of these facts, on its own, is a verdict on identity testing, quality or effect.
Sources: 21 CFR 101.4 - Food; Designation of Ingredients; 21 CFR 101.36 - Nutrition Labeling of Dietary Supplements; FDA - Questions and Answers on Dietary Supplements; NCCIH - Milk Thistle; NCCIH - Dandelion.
