What to Drink for Radiation? Your Guide to Healthy Hydration During Cancer Therapy

October 29, 2025 •

5 min read

Staying properly hydrated is crucial during radiation therapy, as your body is up to 60% water and requires adequate fluid to function correctly. When considering what to drink for radiation therapy, it is important to choose fluids that support healing and manage common side effects like dehydration, nausea, and mouth sores.

Quick Summary

This guide explains the vital role of proper fluid intake during radiation treatment. It identifies beneficial drinks to manage specific side effects and lists beverages to avoid. The article offers practical hydration strategies and tips for patients to maintain their strength and well-being during therapy.

Key Points

Prioritize Water: Aim for 8-12 cups of non-caffeinated fluid daily to prevent dehydration, which is a major concern during radiation therapy.
Manage Side Effects with Fluids: Utilize specific beverages to address common side effects; for example, herbal tea for nausea, ice chips for dry mouth, and broths for low appetite.
Avoid Dehydrating Drinks: Limit or cut out alcohol and excessive caffeine, as these can increase fluid loss and worsen side effects like dry mouth.
Choose Bland, Soothing Drinks for Mouth Sores: If experiencing mucositis, avoid acidic juices (citrus), spicy beverages, or anything excessively hot, as they can irritate sensitive tissues.
Increase Nutrients with Shakes and Smoothies: When solid food is challenging, high-protein and high-calorie nutritional drinks, shakes, and smoothies can help maintain weight and energy.
Consult Your Care Team: Always talk to your oncologist or a registered dietitian to create a personalized hydration plan tailored to your treatment and specific side effects.

The Importance of Hydration During Radiation Therapy

Radiation therapy, while effective at targeting cancer cells, can cause significant side effects that interfere with a patient's ability to eat and drink. Dehydration is a common and serious concern, often caused by side effects such as nausea, vomiting, diarrhea, or a reduced appetite. Maintaining proper hydration is critical for several reasons:

Enhancing Healing: Water and other fluids help transport essential nutrients throughout the body and carry oxygen to cells, which is vital for tissue repair and recovery.
Removing Waste: Adequate fluid intake helps the kidneys flush toxins and waste products from the body, supporting detoxification processes.
Combating Fatigue: Dehydration can exacerbate fatigue, a common side effect of treatment. Staying hydrated helps maintain energy levels and improve overall well-being.
Managing Side Effects: Fluids are essential for lubricating joints, supporting the digestive system, and managing symptoms like dry mouth, which is especially common with head and neck radiation.

Recommended Drinks for Radiation Patients

Choosing the right fluids can make a noticeable difference in how a patient feels during treatment. The goal is to stay hydrated while also soothing sensitive areas and providing necessary nutrients.

Core Hydration Choices

Water: Plain water is always the best option for hydration. If the taste is unappealing due to treatment, try adding slices of lemon, lime, cucumber, or berries to infuse flavor.
Clear Broths: Vegetable or chicken broth can provide fluid and electrolytes, especially when solid foods are difficult to tolerate. Their salty flavor can also help if taste changes make other drinks unappetizing.
Coconut Water: This natural drink is a good source of electrolytes like potassium and has a less acidic profile than some juices. It can help replenish minerals lost from diarrhea or vomiting.
Herbal Teas: Gentle teas like chamomile, ginger, or peppermint can be soothing for nausea. Serve them at a lukewarm temperature, as extreme heat can irritate a sore mouth.

Nutrition-Boosting Beverages

When appetite is low, nutrient-dense drinks can be a lifeline. They provide calories, protein, and vitamins in an easy-to-consume liquid form.

Nutritional Supplements: Oral nutritional supplements like Ensure or Boost are formulated to provide high calories and protein. Talk to your doctor or a registered dietitian before starting any supplements.
Protein Shakes and Smoothies: Homemade shakes or smoothies are an excellent way to get extra protein and calories. Blending fruits, vegetables, yogurt, milk, or protein powder makes for a soothing, nutrient-packed drink. For those with lactose intolerance, non-dairy milks work well.
Sports Drinks: When experiencing vomiting or diarrhea, electrolyte-rich sports drinks can help replenish lost minerals. It's best to dilute them with water to reduce sugar content and to opt for options that are not overly sweet or acidic, which can irritate the mouth.

Addressing Specific Side Effects with Beverages

For Dry Mouth (Xerostomia)

Dry mouth is a very common side effect of radiation to the head and neck. Sips of liquid can provide relief.

Sip Frequently: Keep a bottle of water handy at all times and take small sips constantly throughout the day.
Ice Chips: Sucking on ice chips or sugar-free popsicles can help moisten the mouth and stimulate saliva flow.
Mildly Flavored Drinks: Use flavored water or dilute juices to make them less irritating. Avoid acidic juices like orange, grapefruit, and tomato.

For Nausea and Vomiting

Ginger Tea or Ale: Ginger is well-known for its anti-nausea properties. Try sipping on lukewarm ginger tea or clear ginger ale slowly.
Clear, Bland Fluids: Clear broths or juices like apple juice can be tolerated better than heavier beverages. Sip between meals, not with them, to avoid a full stomach.
Cold Drinks: Some patients find that cold drinks, and even freezing fruits to suck on, are more palatable than warm ones.

For Mouth Sores (Mucositis)

Oral mucositis can cause significant pain and irritation. Selecting the right drinks is important to avoid aggravating the sores.

Soft, Bland Liquids: Opt for soft and bland liquids like milkshakes, smoothies, or diluted broths.
Avoid Irritants: Stay away from acidic juices (citrus, pineapple, tomato), spicy drinks, and those that are very hot.
Glutamine: Some studies suggest that glutamine, mixed in water and swished in the mouth, can help manage oral mucositis. Consult your care team before using it.

Beverages to Limit or Avoid

Just as some drinks are helpful, others should be limited or avoided during radiation therapy.

Alcohol: This is a major dehydrator and can worsen many side effects, including mouth sores.
Caffeine: Caffeinated beverages like coffee and some teas can contribute to dehydration, especially with a dry mouth.
Acidic Drinks: Citrus juices (orange, grapefruit, lemonade) and tomato juice can sting or inflame mouth and throat sores.
Carbonated Drinks: Fizzy drinks can cause gas and bloating, which can be uncomfortable.
Excessively Sweet Drinks: High-sugar juices and sodas can contribute to dehydration and may worsen nausea.

Beverage Comparison for Radiation Side Effects


Drink Category	Benefits During Radiation	Considerations	Avoid if Experiencing	Best for...
Water	Universal hydration, flushes toxins, simple	May taste metallic; infuse with fruit for flavor	None	General hydration, dry mouth
Broths	Electrolytes, calories, soothing	High sodium options might be problematic	Bloating, gas	Nausea, low appetite
Herbal Teas	Soothing, anti-nausea (ginger, peppermint)	Avoid excessive heat if mouth is sore	Taste changes make it unappealing	Nausea, throat soreness
Smoothies	Nutrient-dense, easy to swallow, high calories/protein	Careful with highly acidic fruits (citrus)	Acidic fruit-induced mouth sores	Low appetite, difficulty chewing
Electrolyte Drinks	Replaces lost minerals from vomiting/diarrhea	Often high in sugar; dilute with water	High sugar or artificial flavors	Replenishing electrolytes

Conclusion

Proper hydration is a cornerstone of supportive care during radiation therapy, helping to minimize side effects and support the body's natural healing processes. Patients can find relief by focusing on a variety of fluids, including plain water, broths, and nourishing shakes, while being mindful of specific symptoms like dry mouth or nausea. By avoiding alcohol, limiting caffeine, and staying hydrated with appropriate beverages, patients can manage their symptoms more effectively and maintain their strength throughout treatment. A registered dietitian and the cancer care team are excellent resources to help personalize a hydration plan that best suits a patient's individual needs.

Frequently Asked Questions

While individual needs vary based on health, activity level, and side effects, most radiation patients should aim for at least 8 to 12 cups of fluids per day. Patients experiencing vomiting or diarrhea may need more.

Yes, sports drinks can be helpful for replenishing electrolytes lost due to vomiting or diarrhea. However, they are often high in sugar, so consider diluting them with water and choose less-acidic flavors to avoid irritating mouth sores.

For dry mouth, frequent sips of plain or fruit-infused water are best. Sucking on ice chips or sugar-free hard candies can also stimulate saliva production. Artificial saliva products are also available and can provide relief.

Yes, but with caution. Avoid acidic juices like orange, grapefruit, or tomato, especially if you have mouth sores. Mild juices, like apple or grape, can be good for hydration and energy, or blended into smoothies.

To counter a metallic taste, use plastic utensils instead of metal and try flavorful additions like honey or fruit nectar. Also, consuming cold foods and drinks or sucking on lemon drops may help mask the taste.

For nausea, try sipping on clear, bland fluids like water, clear broths, or lukewarm ginger or peppermint tea between meals. Avoid strong-smelling drinks and fizzy sodas.

Yes, proper fluid intake is crucial for managing diarrhea. Replenish lost fluids with clear broths, water, and electrolyte-replacing drinks. Avoiding caffeine and high-sugar drinks can also help prevent further irritation.