Herbal E-Liquid is made using herb extract instead of tobacco however, a wide range of consumable products are also used.. Naturally Green Anise, Cornsilk as well as a number of flavourful herbs such as mint and lemongrass have been utilized by a wide number of herbal producers. Other non-herbs like rose petals or clover leaves are also used to add flavour. The process involves extracting the goodness, flavours etc. After all the alcohol evaporates the extract is mixed with Vegetable Glycerine or Propylene Glycol (Glycerine). When used for vaping it delivers a very nice throat hit.
The amount of nicotine is negligible as it is extract from herb and vegetable.
Tomatoes and herbs contain more but is non tobacco and is harmless to the human body.Special thanks to Kamiel (Belguim), Pieter (Netherlands) and others who are contributing to the ongoing research and devolopment of our herbal non tobacco based eliquid. Helping us to constantly improve our flavour, a lot of development and expensive research has gone into the production of our herbal mix, in order to gain a throat hit similar to nicotine.

Ingredients: Propylene glycol 30%, Vegetable glycerin 70%, flavourings, Zero nicotine.
https://www.livestrong.com/article/293186-list-of-foods-that-contain-nicotine/