Chemotherapy (chemo) is the use of strong medicines to kill cancer cells. Some people find that these powerful medicines make them not able to think clearly or have a "fuzzy memory." If you've noticed this, it's not all in your head. It's a real side effect of chemotherapy and is often called "chemobrain" or "chemo fog."

Many chemo side effects are well known. They include severe tiredness (fatigue), nausea, vomiting, and hair loss. A common side effect that may be less well known is a decline in mental function. This includes thinking, attention, memory, language skills, and concentration. It's not clear how or why chemo may affect these skills. Some researchers believe that the medicines may directly affect the parts of the brain that control these functions.

A lot of research is being done on chemobrain. Experts are trying to figure out exactly what causes it and what may be done to prevent or treat it. Some studies have shown that people have reported symptoms of chemobrain before even starting treatment. Still others report it even though they have never had chemotherapy. Or they notice the problems when they are getting radiation or hormone treatments for cancer. And in some cases, the symptoms continue for a long time after treatment ends. This information helps researchers learn more about this problem and possible treatments.

The impact of chemobrain varies for each person. A loss of memory or focus can be more disabling for some people than others, depending on their lifestyle and daily use of these functions. For instance, if a busy person has a million things to do every day and has these subtle changes, it might cause more problems. Many times, other people don't even notice the changes. But it can still be very upsetting for the person having them.

Here are some tips to help you cope with chemobrain:

• Limit distractions. When you need to focus on a task, such as paying the bills or cooking dinner, do so in a calm, quiet environment. Limit background noise from the TV or music. Try to not answer the phone until you're done. Don't multitask.
• Practice difficult tasks. If you need to tackle a complex task, you may want to practice it until it becomes very familiar.
• Check in with your brain. If you feel spaced-out or your mind wanders, try asking yourself every few moments, "What am I doing right now?" or "What am I thinking about?" This helps keep you from drifting and helps you refocus.
• Write it down. Keep a journal and a daily planner. Use to-do lists and post reminders for yourself.
• Get organized. Have a specific place for things in the house and office and put things in the same place each time you use them. This can keep you from having to look for them.
• Pump up your mind. Exercise your mind like a muscle. Try crossword puzzles, play sports with your kids, or do any fun thing that keeps you engaged and stimulated. This can also help prevent or control depression, fatigue, and stress.
• Manage stress and get enough sleep and physical activity. High levels of stress hormones decrease mental sharpness, as does a lack of exercise and rest.
• Use mnemonics. These are devices, such as little phrases or catchy songs, that help people remember things.
• Eat well. Try to make fruits and vegetables a big part of your diet. The vitamins and antioxidants in them are good for your brain cells. And they're good for the rest of your body, too.
• Don't have alcohol. Also limit or stay away from other things that might change your mental state or sleeping patterns
• Most important, ask for help. Look to your family and friends, or a doctor. Let your family know that you're having a hard time focusing and may need help or reminders with certain tasks. If you have serious concerns about your memory or focus, talk with your cancer health care team. You may be referred to a neuropsychologist. This is a psychologist who specializes in studying the relationship between the brain and behavior. They may be able to give you more personalized advice.