In Sheltered 2, food poisoning can only be cured with Anti-Emetics given at the beginning of the game or found through scavenging.
As you can imagine, the food in the apocalypse isn't the greatest. When food is low quality, it can make your survivors sick, especially if your pantry is warm. When someone in the bunker has food poisoning, you will be notified in the top left corner and see the survivor start to vomit. Food poisoning will last for around 10 hours if untreated.
As an example, we clocked exactly when one of the survivors fell ill with food poisoning and when the notification said they had recovered. The illness began at 6:09am, and lasted until 16:24pm without any medicine. Thankfully, the duration isn't too long, however, that person will not be able to go on expeditions until well again.
If you have some Anti-Emetics in your medicine cabinet, this will cure the food poisoning straightaway. The player is provided with four at the beginning of the game. After using them, you have to scavenge for more!
Need some more help for Sheltered 2? Why not check out how to stop your bunker from suffocating in Sheltered 2?