Hans needs your help in *Kingdom Come: Deliverance 2*'s main quest, "For Whom the Bell Tolls," involving the treacherous Trosky Castle. Your task? Brew a Fever Tonic using your alchemy skills. Here's how:

Kingdom Come: Deliverance 2 Fever Tonic Recipe & Location

The Fever Tonic recipe resides within the Surgeon's Workshop in Trosky Castle. Access is gained in two ways: stealthily sneaking in, or by convincing the castle Chamberlain you can create a digestive potion for his ailing stomach.

If stealth isn't your style, complete "For Whom the Bell Tolls" objectives up to delivering the horseshoe. Then, speak with Cook Fanka at the forge. Offer to help with her locked chest; she'll lead you to the noble's kitchen. Here, you'll find the ailing Chamberlain. Successfully passing skill checks during conversation will grant you access to the Surgeon's Workshop. Crafting a digestive potion alongside the Fever Tonic further solidifies your access and allows you to meet Thomas.

Failed skill checks? Steal some food, exit the kitchen, and use the courtyard stairs to reach another kitchen entrance (guarded). Bribe the guard with the stolen food, then sneak upstairs to the Surgeon's Workshop. Find the journal on the bookshelf, read the Fever Tonic recipe, and begin brewing.

How to Brew Fever Tonic

The necessary herbs are already prepared at the surgeon's station. Follow these steps:

1. Pour wine into the cauldron.
2. Add 3 handfuls of Feverfew.
3. Lower the cauldron and boil for 2 turns of the sandglass.
4. Grind a handful of Elderberry Leaves with the mortar and pestle.
5. Add the ground Elderberry Leaves.
6. Add 2 handfuls of Ginger.
7. Grab a phial from the bottom left shelf.
8. Distill the tonic using the Still.

Don't fret over failed attempts; ample herbs are available, including those in the room's chest.

With the Fever Tonic complete, locate Thomas. If you earned the Chamberlain's trust, return with both potions. Otherwise, use the noble's kitchen to reach the chapel and find Thomas and his sister, Adele. Speak with Adele to conclude the quest.