The short answer
Lips often dry out and crack during treatment, along with the rest of the mouth. NCI's suggestions include using a lip balm, drinking plenty of liquids, and sucking on ice chips or sugar-free hard candy. Lip pain that interferes with eating, drinking or sleeping should be reported.
Use a lip balm.
Drink plenty of liquids.
Sucking on ice chips or sugar-free hard candy is suggested for dry mouth.
Rinsing through the day with warm water, baking soda and salt is part of NCI's mouth care advice.
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The full explanation.
A small problem that does not feel small
Splitting lips are low on any list of treatment side effects, and they are miserable out of all proportion to their size. They hurt when you talk. They hurt when you smile at a visitor. They make drinking, the thing you are being told to do more of, unpleasant.
So it is worth saying that this is a recognised part of treatment and that there is advice for it.
What NCI suggests
The recommendations sit inside NCI's guidance on mouth and throat problems, in the section about dry mouth:
- Use a lip balm.
- Drink plenty of liquids.
- Suck on sugar-free hard candy or ice chips.
Simple, and worth doing consistently rather than occasionally.
Balm works when it is on your lips, which means keeping one wherever you actually sit.
Why dryness travels together
Treatment can dry out the mouth. Your lips are the visible edge of the same territory, so they tend to go at the same time. That is why the advice arrives as a package: liquids, something to suck on, and balm.
Ice chips and sugar-free hard candy are on the list because they encourage moisture in the mouth itself. They are doing a slightly different job from the balm, which holds moisture on the outside.
Practical habits
A few things that help in real life:
- Put a balm in every place you spend time — bedside, bag, car, infusion chair.
- Apply before sleeping. Mouth-breathing overnight is when lips dry the hardest.
- Keep a drink within reach rather than getting up for one, because reaching is easier than deciding.
- Bring your own supplies to infusion days. Clinic air is dry and appointments are long.
The mouth care around it
Cracked lips rarely arrive alone, so the rest of NCI's mouth care advice is relevant. That includes rinsing your mouth throughout the day with a solution of warm water, baking soda and salt, and asking your nurse to write down the rinse recipe recommended for you.
It also includes checking your mouth daily and reporting any changes, such as pain or sensitivity.
When it stops being cosmetic
Two things move this from an annoyance to a phone call.
The first is pain in your mouth, lips or throat that makes it difficult to eat, drink or sleep. If your lips have got to the point where you are avoiding fluids, that needs to be said out loud to your team.
The second is a fever of 100.4 °F (38 °C) or higher, which is always worth calling about during treatment.
Everything else — the general dryness, the flaking, the way your lips feel tight by evening — is worth mentioning at your next appointment even if it is not urgent. Your team may have a product suggestion that fits your particular treatment.
Words to know
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Common questions
Why do my lips crack when nothing else about my skin has changed?
Dry mouth is a known problem during cancer treatment, and NCI's advice for it includes lip care. Lips sit at the edge of the same dryness.
What actually helps?
NCI names using a lip balm, drinking plenty of liquids, and sucking on sugar-free hard candy or ice chips.
Should I be worried about cracked lips?
The thing to report is pain in your mouth, lips or throat that makes it difficult to eat, drink or sleep, or a fever of 100.4 °F (38 °C) or higher.
Can I use any lip product I own?
Check products with your nurse. Your team knows what you are on and can tell you what to keep and what to leave in the drawer.
Questions to ask your doctor
Being prepared helps you get the most out of your appointments. Save or print these questions.
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Your next step
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Sources last checked: 2026-08-11 what this meansLast updated: 2026-08-20Next planned review: 2027-08-11
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How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and checked line by line against the sources listed on it. That confirms the sources support what the page says. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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