Herbal kits can be used to make herblores if you have acquired the lore and have the items specified in the instructions.
Upgrades
Certain herbalists or individuals offer to improve your herbal kit as a reward. Enhanced herbal kit decreases your chance to mishmash as well as enables a small chance to create more than one mixture.
Spoiler
Grey Havens herbalist
Price: Power-ring or beltDescription: A delicate set of translucent glass measuring cups.
Niuldor
Price: Complete Niuldor's quest to get upgrade. See under Quests. Description: An exquisite retort of polished copper.
Blue Mountains weaponsmith
Price: shining mailDescription: A sharp-edged shining sickle.
Scarred man in Sewers
Price: Find his herbal, that was stolen from him. Herbal loads on one of following mobs: Morthan, Big John, Cinard, Wuda, Wyrdda, Chief smuggler, Bandit leader, Liche, Outcast, Malardil, Experienced trapper Description: A handful of small, silvery bottles and vials.
Thrakghash
Price: After he stops talking, ask Thrakghash research. First, he will ask for herbs you must gather for him (foxtail, gingseng and 2 random). After that bring him rare herblore. Venom, Belladonna doesn't work. Antidote, Arachnia and better will. Description: A fine slender paring knife and a stout chopping knife.
Grobb (Zaugurz orcs only)
Price: Any magic scrollDescription: A mortar and pestle of smooth, white marble.
Sabb
Price: Sabb wears herbal kit with his upgrade on his belt. Kill him to get it. Sabb is a mob that spawns in seasonal Dunland camp Description: A round metal sieve with a mesh of golden threads.
