Custom Toxicity FX Thresholds is a mod for the game The Witcher 3: Wild Hunt. It lets you change the way the game displays certain visual effects, such as when a character has a reaction to something. You can set the percentage of toxicity at which the visual effects are turned on and off. There are four different levels for the face FX in addition to the clean face in the game. The settings can be configured in the in-game menu.

It is very easy to install, but you must first download and install the unification patch if you don't have it yet.