On Thirst-herb: What the Leaves Know, What the Market Sells

The plant the Folk Quarter calls thirst-herb — its proper name is Secca virens, though no one here uses the name — is growing now along every stone edge in the Guild Lane that catches afternoon sun. The leaves are narrow, slightly silvered, and the whole plant does not exceed the height of my hand. If you crush a leaf, the smell is faintly bitter with an undertone of something mineral, like struck stone.

What it is correctly used for: thirst-herb breaks fever sweat. Not the fever itself — that is a different matter entirely — but the wasteful sweating that happens in the second week, the kind that soaks through linen at the small bell and dries by the large one, leaving the patient white as cloth and twice as depleted. A proper infusion, two leaves steeped in hot water until the color reaches pale green, taken three times daily, reduces the sweat. I have given it to seven patients in the last two years. In four of them, the sweat diminished noticeably by the third day. In two, it did not. In one — a woman from Mulov Street — it worked so well that her fever dropped two days earlier than I had anticipated, and she asked me afterward whether I had done something different. I had not. I told her the body had decided its own course and the herb had simply supported what was already occurring. This is the honest account.

What it is not for, despite what the district says: It is not a cure for fever itself. I have heard women in the Bazaar market say that thirst-herb can stop a fever if caught early. This is not true. I have also heard that it strengthens the blood. I have seen no evidence of this. The Weaver’s Street houses have been taking it for the mild fever moving through them — the sweating kind, yes, but the fever itself is still running its course. The herb is reducing a symptom. This is valuable. It is not the same thing as treating the illness.

The drought has now lasted eleven days. The Karvel water is lower than I have seen it since the thaw-flooding of three years ago. The city is drinking less cleanly. I expect we will see more heat cases before the rain comes. If the fever reaches the streets instead of the Wells, thirst-herb will have its moment. I am watching.

I have harvested enough from the stones near the Guild Hall to dry for winter storage. The herb keeps well in paper, away from damp and direct sun. By Frostmonth it will have lost some potency, but the color will tell me when it is no longer reliable — the silver fades to a pale gray. When I see that color, I do not use it.

The body does not lie about what it needs. Neither does the plant that grows to meet that need. The market, however, lies constantly.