Brain fog is when your brain doesn't work as well as usual. It can make it hard to remember things, think clearly, and concentrate. It can also feel like your head is in a fog, like it's hard to focus and you can't think straight. Brain fog doesn't have any special medical name, but it is a symptom of many medical conditions like anxiety, depression, hormonal imbalances, chronic fatigue, allergies, and many others. Taking care of your health, such as eating well, sleeping enough, and exercising can help get rid of brain fog in some cases.