A diagnosis of cancer can turn a person’s life upside down. Multiple trips to clinics for tests and imaging, undergoing treatment and dealing with side effects are among the many challenges of living with cancer.

Almost any cancer treatment can have side effects, which may last anywhere from a few weeks to months or even permanently. Although radiation therapy is generally directed at tumors, other cells are harmed as well. Traditional chemotherapy kills not only cancer cells but also rapidly dividing healthy cells throughout the body, such as those in the gut or hair follicles, leading to side effects like nausea and hair loss.

Targeted therapy, which works against cancer with specific characteristics, may have less of an effect on noncancerous cells and therefore causes fewer side effects. Immunotherapies help the immune system fight cancer rather than attacking cancer cells directly. But boosting immune activity can lead to excessive immune responses that harm healthy tissues, with side effects ranging from fever and flu-like symptoms to organ failure and death. (See Immunotherapy for more information.)

To help you prepare for treatment, ask your doctor or nurse about what side effects you can expect during and after therapy. But remember that side effects vary from person to person. There are many steps you can take to lessen side effects and reduce their impact on your quality of life. If you are having difficulty coping with side effects, tell your cancer care team—they may have helpful advice or may be able to adjust medication doses or switch you to better-tolerated treatment.

Fatigue: People with cancer often feel extremely tired, weak, run-down or lacking in energy. Often resting or sleeping does not help, and cancer-related fatigue can be a stubborn problem. It can be caused by cancer itself, because some tumors compete for the same nutrients as healthy cells. Surgery, radiation and chemotherapy can all trigger fatigue as the body tries to recover. Depression, stress and anemia (low red blood cell count) can also contribute to fatigue. You may not be able to resume your usual activities during or soon after treatment. Try to prepare in advance and ask family and friends for help. Schedule rest periods or naps into your day. A healthy diet and gentle physical activity can help maintain energy and speed healing.

Nausea and vomiting: Nausea and vomiting are common side effects of chemotherapy and radiation, but their severity and how long they last can vary. Try to eat multiple small meals or snacks instead of three large meals. Dry, bland and salty foods can lessen nausea, while foods that are greasy, spicy or have strong odors can make it worse. Peppermint, ginger and medical cannabis may help relieve nausea. Anti-nausea medications (anti-emetics), available both over the counter and by prescription, can often relieve symptoms. (See also Managing Nausea and Vomiting.)

Loss of appetite and weight loss: Some cancers, especially advanced cancer, can lead to loss of appetite (anorexia) and weight loss. Cancer treatments may decrease appetite or alter the way food tastes, making it less appealing. Depression or anxiety can also reduce appetite. At the same time, metabolic changes resulting from cancer can make it harder to maintain or gain weight. Try to eat every few hours and include protein- and calorie-rich foods at each meal or snack. Liquid nutritional supplements can also help. Mild exercise and medical cannabis can often stimulate the appetite. Cancer care teams often include a nutritionist or dietician who can advise you about strategies to improve your appetite and maintain good nutrition. (See also Eating Well When You Have Cancer.)

Mouth and throat problems: Radiation and chemotherapy can cause sores in the mouth and throat that can make eating painful and swallowing difficult. Focus on soft foods and nutrient-rich drinks like shakes and smoothies and avoid salty or acidic foods. Cancer patients should get a dental exam and dental work completed before starting radiation or chemotherapy. Good oral hygiene including frequent tooth brushing and oral rinses can help heal mouth sores.

Diarrhea: Ranging from mild to severe, diarrhea is common in people with cancer. It can be triggered by radiation, medications, stress and other factors. Management depends on the specific cause. Keep hydrated with clear, non-caffeinated fluids. Avoid fatty foods and those that can stimulate bowel activity, such as high-fiber fruits and vegetables and coffee. If needed, ask your doctor or nurse about antidiarrhea medications.

Constipation: Constipation can be caused by changes in eating habits and being less active during treatment, or it can be a side effect of certain medications, especially opioid pain relievers. Drink plenty of fluids and increase dietary fiber by eating raw fruits and vegetables, whole grains and nuts. Mild exercise often encourages bowel movements. Ask your doctor about laxatives or other medications if constipation is severe or prolonged.

Pain: Not everyone with cancer experiences pain, and it is more likely during advanced cancer that has spread throughout the body (known as metastasis). Tumors that press on nerves or organs or invade the bones can cause pain. Pain may also result from surgery, radiation or chemotherapy. Pain can vary in intensity and may be acute (short-term) or chronic (long-term). Pain management depends on its specific cause. Sometimes it can be managed with over-the-counter medications. If pain is severe or chronic, stronger medications such as opioids may be needed and your doctor may refer you to a pain specialist. (See also Managing Cancer-Related Pain.)

Peripheral neuropathy: Some chemotherapy drugs can cause peripheral neuropathy, or nerve damage in the extremities. Neuropathy can decrease sensation and cause pain, burning, tingling or numbness in the hands and feet. In severe cases it can interfere with walking and other daily activities. Neuropathy can also lead to difficulty urinating or constipation. Studies show that wearing frozen gloves and socks during chemotherapy infusions can help prevent neuropathy in the hands and feet. In some cases chemotherapy drugs may be given in smaller doses over a longer period to reduce nerve side effects.

Hair loss: Also called alopecia, hair loss is a common side effect of chemotherapy and radiation. It happens because these treatments can kill the fast-growing cells of the hair follicles. But not all cancer drugs lead to hair loss, and the amount of hair lost varies among individuals. Hair loss can occur gradually or quite quickly, and it often begins two to three weeks after starting chemotherapy or radiation. Studies show that scalp cooling during chemotherapy infusions can help prevent hair loss. In most cases, hair loss is temporary and it will grow back after stopping chemotherapy.


Low blood cell counts: Radiation and some chemotherapy drugs can impair the bone marrow’s ability to produce blood cells, including red blood cells, white blood cells and platelets. Low levels of red blood cells—and oxygen-carrying hemoglobin—lead to anemia, with symptoms such as fatigue, shortness of breath and dizziness. Low levels of white blood cells, which carry out immune responses, can make people more prone to infections. Low platelet levels can lead to easy bruising or bleeding. People with low white blood cells should take precautions to avoid infections, including safe food preparation. It may be necessary to limit contact with other people when white blood cells are very low. Erythropoietin can be given to stimulate red blood cell production, while colony-stimulating factors encourage white blood cell production.

Sexual side effects: Cancer and its treatments can affect sex drive (libido) and sexual function, which in turn can affect relationships with partners. This is especially likely with drugs that interfere with the sex hormones estrogen or testosterone. Cancer surgery and treatment can alter a person’s appearance in terms of weight changes, scars or losing a body part, which can lead to self-consciousness and feeling unattractive. Women and men may experience changes in sexual function, such as not feeling aroused or being unable to reach orgasm. Women may experience symptoms of early menopause and men may have trouble getting an erection. It can take time and effort to maintain the same level of intimacy that was possible before cancer. A sex therapist or marriage counselor may be able facilitate communication and help set realistic expectations. (See also Sexual Health When You Have Cancer.)

Effects on fertility: Some cancers and cancer treatments affect the reproductive system, which can lead to fertility problems. Radiation and chemotherapy can have harmful effects on eggs and sperm. Removal of cancer in reproductive organs such as the uterus, ovaries or testicles can affect a woman’s ability to become pregnant or a man’s ability to father children. Some surgeries cause permanent infertility, which can be a concern for people who develop cancer as children or young adults. Fertility counseling should be done before treatment begins, including discussion of available options such as freezing eggs or banking sperm. (See also Fertility Issues When You Have Cancer.)

Psychological well-being. Feelings of depression and stress are common among people with cancer, as well as their family members and loved ones who are helping them through it. Sadness, anger, fear, grief, frustration and a sensation of hopelessness are common too, especially when cancer treatment lasts a long time, the cancer comes back or spreads, or a person has cancer that cannot be treated. If these feelings are interfering with relationships or normal activities, seek help from your cancer care team. Depression and other mental health concerns can often be managed with counseling, medication or a combination approach.

For more information on managing side effects, visit:

American Cancer Society
National Cancer Institute
American Society for Clinical Oncology

Last Reviewed: November 10, 2017