Alchemy in Witcher 3 is much more advanced topic than crafting. With its help Geralt can obtain many items that can be used in various ways. In general alchemy is used for four main reasons:
- Using potions - Elixirs can be helpful in regenerating health, increasing resistance to specific attack forms or in increasing combat effectiveness.
- Using bombs - Bombs are especially useful when you must defeat some strong opponents and when you must destroy some monster nests.
- Placing oils on weapons - It's a very important part of alchemy if you're playing on one of the higher difficulties. Using the correct oil (check the bestiary entries in which enemies' weak points are listed) might make it much easier to defeat some strong monster.
- Drinking decoctions - they are much stronger than potions but they greatly increase Geralt's toxicity level.
Alchemy items preparation process is slightly similar to crafting, although there are many differences as well. In order to create an item related to alchemy you must have its recipe. Recipes can be found in the game world, received from witcher contracts or bought at merchants (herbalists usually have the largest amount).
Important - Some formulas can be found in more than one versions - basic, advanced and master. Try to obtain better receipts for objects that you use regularly. It will make them work more effectively.
In addition to the recipes you must gather the required alchemy ingredients. Some of them are easy to gain, like flowers taken from the bushes. Others can be bought at merchants or found in chests. There are very rare ones as well, to obtain them you must kill specific monsters (for example, drowner's brain). It is wise to loot enemy's corpse after each battle. The ingredients you will gather can later prove to be useful.
Having the recipes and ingredients allows you to create an alchemy item. What's important, you must make it only once. Of course, you can't use a single potion, oil or bomb with no limits, each item has specific number of uses. After you use all your supplies, you must replenish them. It can be done by meditating. The game will replenish your supplies of alchemy items as long as you have the strong alcohol Alcohest (it can be bought from innkeepers, found in chests and other containers in the game world or created in alchemy tab).
Most useful alchemy items available from the beginning of the game are:
- Cat potion - it allows Geralt to see in the dark; very useful when exploring caves and dungeons
- Swallow potion - it allows you to regenerate health much faster than when using standard food
- Thunderbolt potion - temporary raises Geralt's attack power
- Grapeshot bomb - it deals large fire damage to enemies and can be additionally used for destroying monster nests
- Dragon's Dream bomb - it spreads poison gas. You can then burn the gas with Igni sign and create a series of powerful explosions
- Necrophage oil - many basic monsters (for example, ghouls) have low resistance to effects caused by this oil