Stardust is a drug and is currently the only named drug in the story. Stardust comes in powder form, and can be taken via injection, ingesting, or inhaling. It gives the users a strong euphoric, and erotic high that can last several hours. It is potently addicting, and isn't that uncommon in Haven in poor areas or places of vice. It is made from an extract of the seeds of Star Trees, which can be found in the base of the leaves.
It is much, much more common across the seas to the east, where the notorious pirates The Suns of The East are global distributors.