While Sekiro: Shadows Dies Twice changes with certain elements expected of FromSoftware's games, it certainly doesn't hold back on ruthlesness. Repeated deaths will lead to characters across the world violently coughing, which is when you might want to look for a Dragonrot cure.
Here's everything about how to cure Dragonrot and what the disease does.
How to Cure Dragonrot?
Although Sekiro: Shadows Dies Twice allows protagonist Wolf to resurrect shortly after falling in battle, it does so at a cost. While you do hang on to both Skill Experience and sen, the more you resurrect, the more Dragonrot spreads across the world, infecting those encountered by Wolf. Not only can it stop you from completing quests, it also reduces the chance of receiving Unseen Aid, which is a trait that can make it so that you don't lose your sen and Skill Experience upon dying.
You'll know people are infected with the disease since, when that happens, Rot Essence items will appear in your inventory, under the Key items section. How do you cure Dragonrot, then? The Sculptor will eventually become sick, which will prompt Emma the Physician to let you know that she thinks she can make a Dragonrot cure.
Afterwards, when you encounter someone else coughing from Dragonrot, you'll be able to collect a blood sample from them. Give the blood sample to Emma in the Dillapidated Temple and she'll begin fashioning a cure. Once she's finished, which does take a while, you'll receive the Dragon’s Blood Droplet and the Recovery Charm items. Use them at a Sculptor's Idol, where the Dragonrot Restoration option is now available and that will cure Dragonrot from all those affected.
The Dragonrot cure might last a while, but remains nonetheless temporary. Resurrecting does eventually bring the disease back and, while you will be able to purchase Dragon's Blood Droplets from certain merchants, the available amount is limited. Thus, you'll not only have to do your best to resurrect less but also be mindful about picking the right moments to cure Dragonrot if you want to keep those you encounter healthy.