What are the side effects of chemotherapy?

The 10 most common side effects include:

1. Illness and a weakened immune system

Cancer and the treatment of it can weaken the immune system. Because chemotherapy kills healthy immune cells, it can make a person more vulnerable to infection. Since a person’s immune system will be less able to fight off germs, infections may also last longer. Eating a healthful diet, frequently washing hands, avoiding people who are ill, and seeking prompt medical care for signs of illness can reduce the risk of serious infections.

2. Bruising and bleeding more easily

Chemotherapy can cause a person to bruise or bleed more easily. Many people having chemotherapy experience this side effect, and it does not usually cause concern. However, bleeding following a serious injury can be dangerous. So it is a good idea to take precautions, such as wearing gloves when gardening or cutting food. Also take proactive steps to reduce falls and the risk of injury. People should contact a doctor for any serious wounds, or for a bruise or injury that seems to be healing very slowly.

3. Hair loss

Chemotherapy can damage hair follicles, causing the hair to weaken, become brittle, and fall out. Any hair that regrows may be much thinner, or a different color. This pattern usually continues until chemotherapy ends. Hair almost always regrows after chemo. A study in the journal Skin Therapy Letter estimates that 65 percent of people receiving chemotherapy experience hair loss. No specific treatment can guarantee hair loss prevention, but proper hair care may slow the loss of hair and promote regrowth after treatment.

4. Nausea and vomiting

Nausea and vomiting can come on suddenly, appear after each chemotherapy session, or happen seemingly at random. Dietary changes, such as eating smaller meals or avoiding certain foods, can help. Anti-nausea drugs may also be helpful, particularly for people who experience nausea at predictable intervals, such as immediately after chemotherapy.

5. Neuropathy

Neuropathy is nerve pain caused by damaged nerves. It often affects the hands and feet, causing tingling, numbness, and unusual electrical sensations. Some people also experience weakness and ringing in the ears. Neuropathy is often worse in people who take certain chemotherapy drugs, according to a 2014 review in Cancer Management and Research. Research into the prevention of neuropathy is mixed, but lotions containing menthol and supplements, such as calcium and magnesium, may help. More research is necessary.

6. Trouble breathing

Sometimes, chemotherapy can damage a person’s lungs, reducing their capacity, which makes it harder for them to get the oxygen they need. Breathing issues can also be a side effect of some types of cancer. Staying calm, breathing deeply, and sitting down while elevating the upper body with pillows may help. A doctor may prescribe medication or oxygen therapy if breathing problems continue.

7. Constipation and diarrhea

Chemotherapy may trigger digestion problems because it can damage cells that help digestion. Other side effects of chemotherapy, such as nausea, can force people to change their diets. These sudden changes can also cause digestive problems. Avoiding foods that irritate the stomach may help, and over-the-counter remedies for constipation, such as magnesium, can make bowel movements less painful. Proper hydration can reduce the severity of constipation and also prevent dehydration due to diarrhea, which can also be a side effect of chemotherapy.

Moderately common side effects of chemotherapy include:

8. Rash

Chemotherapy can cause changes in the immune system that trigger rashes and other skin changes. Severe rashes can cause painful itching, and there is a risk of infection if a person scratches a rash until it bleeds. Moisturizing lotions and over-the-counter anti-itch creams can help with many rashes.

9. Mouth sores

Some people notice painful sores in their mouth 1 to 2 weeks after having some forms of chemotherapy. The soreness can vary in severity. Sometimes, the sores may bleed or become infected. Using a non-abrasive toothpaste can help. Some people find relief from rinsing their mouth with warm salt water. Numbing gels may also help. People should see a doctor for treatment if the sores are very painful or weeping.

10. Pain

Generalized pain, including chronic muscle pain, headaches, and other aches and pains, is common after chemotherapy. For some people, this pain may be due to stress and the tension of a cancer diagnosis. Nerve damage due to chemotherapy may also cause pain. The severity of the pain varies. Massage, rest, and relaxation exercises can help with muscle pain. Some types of exercise may also offer some relief, but people should consult a doctor before beginning a new exercise routine. Sometimes, a doctor may recommend other treatments, such as chiropractic care, physical therapy, or pain medication.