Foods to Avoid During Chemotherapy: A Safety Guide

During chemotherapy, your immune system is compromised, making food‑borne illnesses more dangerous. Choosing foods that are thoroughly cooked, properly washed, and safely stored can reduce infection risk and support treatment.

Catalina Ruz Gatica, a registered dietitian specializing in chronic illness at Top Nutrition Coaching in Chicago, advises, “Patients undergoing chemotherapy should steer clear of undercooked or raw meats, raw fish, expired products, and any produce that hasn’t been washed.”

Even foods that appear harmless—such as Caesar dressing, which may contain raw egg—can pose a hidden risk.

Dry‑cured or smoked meats

Items like dry‑cured salami or smoked fish are preserved by salting, drying, and smoke exposure. Although these methods slow bacterial growth, they don’t guarantee the same level of pathogen elimination as high‑heat cooking.

Unpasteurized dairy and milk products

Pasteurization uses heat to destroy harmful microbes in dairy, juices, deli meats, egg products, and nut butters. During chemotherapy, avoid raw milk, unpasteurized yogurt, and soft or blue‑veined cheeses made from unpasteurized milk, including:

• Blue cheese
• Brie
• Stilton
• Roquefort
• Gorgonzola
• Queso blanco fresco

Open‑case deli items and bulk‑bin foods

Salads, sliced meats, and other items kept in deli coolers are exposed each time the case is opened, increasing the chance of contamination. The same applies to bulk‑bin products—cereal, nuts, or spices—where you can’t verify what previous users may have introduced.

Unwashed fruits, vegetables, and sprouts

Fresh produce is essential for nutrition, but it must be washed or cooked to remove surface microbes. This rule also covers packaged items like salsa, unpasteurized “fresh‑squeezed” juices, and especially sprouts, which are prone to bacterial growth.

Undercooked meats

Cooking meat to the recommended internal temperature kills both surface and internal pathogens. Avoid any meat that is pink inside, as well as raw preparations such as sushi, sashimi, and lox.

Raw or lightly cooked eggs

Raw eggs can harbor Salmonella. Foods that often contain raw egg include:

• Smoothies
• Homemade eggnog
• Homemade mayonnaise
• Unbaked cookie dough
• Hollandaise sauce
• Caesar salad dressing

Raw nuts and fresh nut butters

Despite low moisture, raw nuts can still carry Salmonella. Choose roasted nuts or commercially pasteurized nut butters to lower risk.

Cream‑filled pastries

Baked goods with cream fillings contain dairy that can support bacterial growth if not kept properly refrigerated.

Raw honey or honeycomb

Raw honey is debated for its potential anticancer properties, but it may also contain spores that cause botulism. Use only pasteurized honey during treatment.

Untreated water sources

Drinking water from wells, springs, or streams can introduce harmful microorganisms. Stick to filtered or bottled water unless you’re certain the source is safe.

While you’ll need to avoid the foods listed above, you can still enjoy a wide range of nutrient‑dense options. Foods rich in vitamins A, C, E, selenium, and zinc—such as sweet potatoes, broccoli, squash, pumpkin seeds, lentils, salmon, and eggs—support immune function.

Ruz Gatica recommends, “If chemotherapy suppresses appetite, eat small, frequent meals that include these immune‑boosting foods to meet energy needs without aggravating symptoms.”

Effective diet management helps prevent infection, maintain body weight, and provide the nutrients necessary for healing. As Ruz Gatica emphasizes, “What’s on your plate matters; a well‑balanced, safely prepared diet keeps your body’s engine running smoothly throughout treatment.”

By prioritizing thoroughly cooked foods, washed produce, and safe storage practices, you can lower the risk of food‑borne illness and stay stronger during chemotherapy.