Can nausea and vomiting from chemotherapy be prevented?

Often, yes. The National Cancer Institute says antinausea medicines work well to prevent and relieve nausea and vomiting in people with cancer. The key sentence is about timing. These drugs are given before chemotherapy starts, because once nausea and vomiting from chemo develop, they are more difficult to treat.

Four different problems with one name

NCI splits nausea and vomiting by when it happens, and the split matters because each type is handled differently.

• Acute: within 24 hours after treatment starts.
• Delayed: 1 to 7 days after treatment. Also called late.
• Anticipatory: before treatment even begins. After a bad session, the smells, sights, and sounds of the treatment room can trigger it on the next visit.
• Chronic: continuing after treatment ends.

Two more terms describe how well the medicines are working. Breakthrough nausea happens within 5 days of starting antinausea treatment. Refractory nausea does not improve with the medicines at all. Both are reasons to call, not reasons to wait.

NCI gives a rough duration for chemotherapy: usually 24 to 48 hours, though some people feel sick for up to 7 days.

The drug classes, and why more than one is used

NCI names seven groups, and it is common to receive drugs from several at once because they block different triggers.

• Serotonin blockers: ondansetron, granisetron, dolasetron, palonosetron.
• Dopamine blockers: chlorpromazine, prochlorperazine, promethazine, metoclopramide.
• NK-1 receptor blockers: aprepitant and fosaprepitant.
• Steroids: dexamethasone and methylprednisolone.
• Benzodiazepines: alprazolam and lorazepam, which work on anxiety-related nausea.
• Antipsychotics: olanzapine, which blocks several brain pathways at once.
• Cannabinoids: dronabinol.

Anticipatory nausea explains why a benzodiazepine sometimes appears on the list. That form is a learned response, not a chemical one, so a drug aimed at anxiety can be the right tool.

Why prevention is treated as urgent

Uncontrolled vomiting causes real harm. NCI names dehydration, electrolyte imbalance, and weight loss.

Dizziness, weakness, or confusion are the signs of dehydration NCI tells caregivers to watch for. Any of those, or vomiting that stops fluids going down at all, means calling the treatment team the same day rather than waiting for the next appointment.

The everyday measures that add to the medicine

NCI's practical list is concrete. Sip fluids through the day: water, broth, juice, ginger ale, tea, or sports drinks. If weight is dropping, choose fluids with calories over plain water.

Cold foods often go down when hot ones will not, so popsicles, pudding, yogurt, and gelatin are worth trying. So are bland starches such as toast, rice, plain pasta, crackers, and pretzels. Ginger ale and ginger tea may ease it.

Skip greasy, fried, sweet, or spicy food if it causes trouble. Avoid strong smells while eating, including coffee, fish, onions, and garlic, and ask someone else to cook when smells are the problem.

Five or six small meals beat three large ones. After eating, resting upright or with the head raised for 30 minutes helps.

NCI also says acupressure can relieve nausea when used alongside medicine, and that relaxation techniques such as deep breathing, guided imagery, hypnosis, massage, and music can reduce it. One warning attaches to all of it: check with a doctor before any supplement or alternative therapy, since some make cancer treatments work less well.

Keeping a short record of when nausea hits, and what came before it, helps the team adjust. Our guide to nausea and vomiting covers management in more depth, and our chemotherapy page covers what to settle in advance.

NCI's page was last updated on May 9, 2025.

Sources

• https://www.cancer.gov/about-cancer/treatment/side-effects/nausea-vomiting