Lilac Wine is a heady brew, made by a special necromantic ritual, that allows the maker to keep the distilled power of a death charge in bottle form.
It's death. In liquid, drinkable, form.
It is not poisonous, and probably doesn't have any alcohol in it, though it would be hard to know, since people who drink it can lose hours, even days. It is said to give visions, or hallucinations.