On Death's Bed is a Side Quest in White Orchard. When Geralt arrives to speak with the local herbalist, Tomira, he finds that a young woman named Lena has been fatally wounded by a Griffin, and will likely not survive the night.

On Death's Bed Walkthrough

Though not a big quest by any means, you will have the chance to get some free items that may prove useful in other side quests in the area.

Geralt will mention that the only way to save her might be to give her one of his Swallow potions, but as they are only for Witchers, she may not react well to it. At this point you can either forget about her and be on your way, or craft the potion - which you should probably do anyway as it is both a useful potion, and can be replenished easily once made.

As for the ingredients - Dwarven Spirit is readily found in containers, or can be bought from merchants. Celadine is found from plants in the region (look for yellow buds), and Drowner Brains can be looted off of Drowners lurking along the riverbanks, or in the swamp to the North.

Once you have all the ingredients, craft the potion, and talk to the Tomira to give one potion to Lena. You'll be able to replenish it just by Meditating (and having at least one form or pure alcohol on hand). In reward for your efforts, Tomira will give you the recipe for Specter Oil, as well as book that will give you knowledge about Wraiths, Noonwraiths, Nightwraiths, and Plague Maidens. Both of these rewards will be extremely useful for another side quest in this area - Contract: Devil by the Well.