What happens if you don't drink enough water on chemo?
Matthew Alvarez
Published May 10, 2026
Cause of dehydration
Cancer and some treatments such as chemotherapy, targeted cancer drugs and immunotherapy can cause the following side effects: vomiting. diarrhoea. sweating because of a fever.Should you drink lots of water during chemo?
Drinking a lot of water during your chemotherapy treatment is also important. Your treatment and some medications have side effects that could cause severe dehydration. Make chemotherapy hydration a priority. When you drink plenty of water during treatment, it can help make your recovery a smoother process.How much water should I drink a day on chemo?
Sip all day.Some health experts suggest at least 8 glasses of liquid a day, even more if you have diarrhea or vomiting. Ask your doctor how much sounds right for you.
How do you stay hydrated during chemo?
Try to increase the amount of water and other liquids you drink. (Multivitamins can sometimes darken urine, so keep that in mind if you're taking one.) Drink a lot. Water, pasteurized 100% fruit juices, milk, and low-sodium broth are good choices for staying hydrated while you're in treatment.How do you get a cancer patient to drink water?
Think beyond water“A lot of patients have difficulty with water, so it doesn't have to be water,” says Cruz. “Things with electrolytes like coconut water, soups and broths, Jell-O, smoothies — those can be good alternatives to water.” Remember that fluids don't always have to come in the form of a drink, either.
All the Signs That You’re Not Drinking Enough Water
What is the best drink for cancer patients?
The National Cancer Institute (NCI) provides the following list of clear liquids:
- Bouillon.
- Clear, fat-free broth.
- Clear carbonated beverages.
- Consommé
- Apple/cranberry/grape juice.
- Fruit ices without fruit pieces.
- Fruit ices without milk.
- Fruit punch.
How do you tell if someone is dehydrated after chemo?
What are the signs of dehydration?
- feeling thirsty.
- experiencing dry mouth, lips, gums, and nostrils.
- increased headaches.
- dizziness.
- confusion.
- sleepiness.
- decreased energy.
- darker urine color and decreased urination.