In Jain Dharma, the main question is always: “Is there himsā (violence) or not?” So let’s separate two things:

1. Eating / consuming root vegetables

- Potato, onion, garlic, carrot, beet, etc. are avoided because they are roots. - Uprooting them kills many living beings in the soil and the whole plant. - So, eating such things is generally not allowed for a Jain following ahimsā strictly. ( jainknowledge.com)

1. External use (cream/serum/lotion with root extracts)

- You are not eating it, only applying on skin. - From the strict ahimsā point of view, the main violence has already happened at the time of harvesting the root. - Using a ready‑made product externally does not add much new physical himsā (like killing insects, etc.) in your act at that moment.

So practically, for most śrāvaks (householders):

• Using a cream/serum with root‑vegetable extract on the body is generally tolerated, because it is not food and not causing fresh killing by you.
• However, a very strict practitioner who wants maximum purity (like during Paryushan, special vows, or very high personal standards) may choose to avoid such products also, just to keep bhāva (inner intention) very clean and detached.

Simple guidance:

• Daily normal life:

- If it is difficult to avoid, you may use such products on the external body. - While using, keep the feeling: “I don’t support himsā; I wish all beings well.”

• Higher vows / special days / if you can easily avoid:

- Choose products without root‑vegetable ingredients, if possible. - This is closer to uttam ahimsā (the higher ideal).

If you want to understand Jain food restrictions more clearly, you can read more here: Allowed & avoided foods in Jainism