When rats and mice are given saccharin (an artificial sweetener), sometimes their liver gets more inflamed, sometimes their gut gets less inflamed, and sometimes nothing changes—so the effect depends on how much they get, how long they get it, and what health condition they have.

This study looked at how saccharin affects inflammation in animals and found that sometimes it makes inflammation worse, sometimes it doesn’t change anything, and sometimes it even helps—depending on how much and how long the animals were exposed, which is exactly what the claim says.