Substances on Roshar include various naturally occurring poisons, antiseptics, numbing/stimulating agents, sedatives, sealing agents, herbs, and wines. Amongst those mentioned thus far are the following:
Backbreaker powder is a very lethal poison. It was used by Kabsal in his attempt to assassinate Jasnah.
Blackbane is one of Roshar's most deadly natural poisons. It has a narrow, dark green leaf with a point divided in three; a trefoil prong. It had to be dried out before reaching its potency.
Conicshell mucus is used for the numbing of a wound.
Fourleaf sap is a salve that prevents infection.
Gulket sap, from the plant's leaves, when rubbed on sore muscles, makes them feel warm and cold at the same time.
Horneater lager is so strong that it melts cups.
Knobweed milk or knobweed sap is a powerful antiseptic, created from knobweed.
Lavis grain beer, ale and liquor (or hard honu).
Lister's oil is a salve that prevents infection.
Longroot can be used to make stew and tastes faintly of minerals. Easily cultivated brown roots, they grow in cracks in stone where water collects after storms. They are sticky when sliced into and likely layered with crem on the outside.
Weevilwax is a sealant for messages within envelopes sent between contacts. There is a standing mirror within Dalinar's rooms at Urithiru that is framed by a border which has the look of something that had been carved first in weevilwax, then Soulcast into hardwood.
Wine comes in several colors. Blue, orange, violet and yellow have been mentioned. Blue is a strong vintage. Orange is commonly consumed among members of the ardentia. Violet is among the strongest of liquors. Yellow has the weakest 'alcohol' content.
Winterwort is a bitter tasting plant, used to induce sleep. Crushed into powder, mixed with oil and one spoonful per ten brickweight of the person you're drugging, it will induce a deep sleep for about five hours. Its bitterness makes it safer to keep than other alternatives, since people won't eat it by accident.