AGROVOC

Anthelmintic: an agent that destroys internal parasites. (https://www.fao.org/dairy-production-products/resources/glossary/en/?index=a)

A merchant is a person who trades in commodities produced by other people, especially one who trades with foreign countries. Historically, a merchant is anyone who is involved in business or trade (https://en.wikipedia.org/wiki/Merchant)