What Is Chemo Brain?

Medically Reviewed by Jennifer Robinson, MD on March 23, 2024
Written by WebMD Editorial Contributors
3 min read

Chemotherapy can help you fight cancer, but side effects are almost certain. It’s common for you to have a cloudy mind, called "chemo brain," during and after treatment. Maybe you have a hard time remembering names or can’t multitask as well as you used to.

As many as 3 out of 4 people with cancer say they're not as mentally sharp. It’s often caused by your chemotherapy medicines, but it can also come from the cancer itself or other problems like infection, low blood counts, fatigue, sleep problems, or stress.

Chemo brain can cause thinking and memory problems. Symptoms include trouble with:

  • Concentrating and paying attention
  • Remembering names, dates, and everyday things
  • Finding the right word or doing simple math (like balancing your checkbook)
  • Doing more than one thing at a time
  • Mood swings

If you’re in a mental fog, talk to your medical provider. They will ask about your symptoms. They will also want to know when your problems started and how they affect your everyday life.

Your doctor may ask what makes your symptoms worse and better. Do you, for example, feel better in the morning than at night? Does it help when you're active, when you eat, or after you've rested?

Bring a list of all the medicines you take, even if they aren't for cancer.

If chemo brain is disrupting your daily life, your doctor may suggest a counselor or psychologist. There are other things that can help too, including:

  • Some stimulants and antidepressants
  • Exercise -- even 5 minutes a day
  • Plenty of sleep and rest
  • Exercising your brain with puzzles, playing an instrument, or learning a new hobby

Simple strategies can help with memory loss and confusion. Try these tips:

  • Carry a daily to-do list with reminders.
  • Don't multitask. Do one thing at a time so you're not distracted.
  • Put sticky notes around your home and office. Set reminders on your smartphone, too.

Often, the fogginess will fade when your chemo ends. But for some people, the fuzzy feelings will linger for several months or sometimes a year or more.

For those with lasting symptoms, researchers are looking at medicines for diseases like depression, ADHD, Alzheimer’s, and other types of dementia. But more testing needs to be done.

If you have chemo brain that persists and you’ve tried all the self-help tips, talk with a neuropsychologist. This is a doctor who specializes in the brain and can help with attention span and memory. They will find areas where you need help and tell you if other treatable problems like depression, anxiety, and fatigue are to blame.

You’re not just imagining this. Studies show that cancer and its treatment causes changes in the brain. 

Don’t be afraid to ask your family and friends for support and gentle reminders. Support groups are another great idea.