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Chemotherapy (“chemo”) is an effective treatment that kills cancer cells, but it can also affect healthy fast-growing cells in the body. This is why side effects can occur. Not everyone has the same side effects. Your experience depends on the chemotherapy drugs used, your dose, your schedule, and your overall health.
Many side effects are temporary and can be treated or reduced with medications and supportive care.
Common Chemotherapy Side Effects
Fatigue
Fatigue is one of the most common side effects of chemotherapy. Many patients describe it as deep exhaustion that does not improve with rest alone.
Tips to manage fatigue:
Pace yourself and rest when needed
Light daily movement (such as short walks) can help
Stay hydrated and eat small nutritious meals
Ask your doctor to check iron levels and blood counts
Nausea and Vomiting
Some chemotherapy medications may trigger nausea and vomiting. This can happen within hours or days after treatment.
Important: Anti-nausea medicines (antiemetics) are very effective, and work best when taken early.
Helpful strategies:
Take prescribed nausea medicines exactly as directed
Eat small meals, more often
Choose bland foods (rice, toast, soup)
Avoid greasy or strongly scented foods
Appetite Loss and Taste Changes
Chemo can affect the sense of taste and smell. Food may taste metallic, bitter, or simply “off,” and your appetite may decrease.
What can help:
Try protein drinks or smoothies
Use plastic utensils if foods taste metallic
Try mild flavors and soft foods
Focus on small, frequent meals instead of large meals
Hair Loss or Hair Thinning
Some types of chemotherapy cause hair loss or thinning, typically starting 2-3 weeks after the first treatment.
Good to know:
Hair usually grows back after chemotherapy ends
Regrowth may look or feel different at first
Low Blood Counts
Chemotherapy can temporarily reduce the body’s ability to make blood cells. Based on the cells lost, this may cause various side effects.
Low white blood cells (neutropenia): Increased risk of infection
Low red blood cells (anemia): Weakness, fatigue, shortness of breath
Low platelets (thrombocytopenia): Easy bruising or bleeding
Increased Infection Risk
Because chemo can lower white blood cells, infections can become serious quickly.
Call your doctor right away if you have:
Fever
Chills
Sore throat
Cough
Burning with urination
Redness/swelling near a port or IV site
Mouth Sores (Mucositis)
Chemo can cause painful mouth or throat irritation, including sores.
Self-care tips:
Use gentle mouth rinses as recommended
Choose soft foods (yogurt, porridge, soups)
Avoid spicy, acidic, or rough foods
Ask your doctor about prescription mouth rinses if needed
Diarrhea or Constipation
Some chemo drugs may cause diarrhea, while medications like anti-nausea drugs or pain relievers may cause constipation.
When to seek help:
Severe diarrhea can cause dehydration, and needs medical attention
Constipation lasting several days should be reported
Peripheral Neuropathy (Nerve Pain or Numbness)
Some chemotherapy drugs can irritate nerves, causing:
Tingling or numbness in fingers and toes
Burning pain
Weakness or trouble with balance
Difficulty with fine motor tasks (buttons, writing)
Important: Report symptoms early. Dose adjustments can help prevent long-lasting nerve damage.
Skin and Nail Changes
Chemo can cause changes such as:
Dry skin or rash
Darkened skin patches
Nail discoloration, ridging, or tenderness
Less Common but Serious Chemotherapy Side Effects
Most chemotherapy side effects are temporary and manageable. However, some side effects are less common but potentially serious, and may require urgent medical attention or treatment changes.
Always tell your oncology team right away if you notice new or worsening symptoms.
Serious Infection (Neutropenic Infection)
Chemotherapy can lower white blood cells (neutrophils), making it harder for your body to fight infection. Even a minor infection can become dangerous quickly.
Call your doctor immediately if you have:
Fever 38°C (100.4°F) or higher
Chills or shaking
Sudden sore throat
Persistent cough or shortness of breath
Burning when urinating
Redness, swelling, or pain around an IV/port site
Important: A fever during chemotherapy is considered a medical emergency until proven otherwise.
Severe Dehydration (from Vomiting or Diarrhea)
Repeated vomiting or diarrhea can quickly lead to dehydration and electrolyte imbalance.
Contact your care team urgently if:
You can’t keep fluids down
You are vomiting repeatedly
You have diarrhea more than a few times per day
You feel dizzy, faint, or extremely weak
You have dark urine or urinate very little
Blood Clots (Deep Vein Thrombosis or Pulmonary Embolism)
Cancer and chemotherapy increase the risk of blood clots.
Seek emergency care if you have:
Sudden swelling or pain in one leg
Redness or warmth in the calf or thigh
Sudden shortness of breath
Chest pain (especially with breathing)
Sudden fast heartbeat or unexplained anxiety
Allergic or Infusion Reactions
Some chemotherapy drugs can cause allergic reactions, often during or shortly after infusion.
Symptoms may include:
Rash or hives
Itching
Swelling of face/lips/throat
Wheezing or difficulty breathing
Chest tightness
Dizziness or fainting
These reactions can usually be treated quickly when caught early, so it’s important to report symptoms immediately during infusion.
Heart Damage (Cardiotoxicity)
Certain chemotherapy agents may affect heart function, including weakening of the heart muscle in rare cases.
Contact your doctor right away if you develop:
New shortness of breath (especially at rest or lying flat)
Swelling in ankles, feet, or legs
Sudden weight gain
Chest pressure or pain
Unusual fatigue that rapidly worsens
Lung Inflammation (Pneumonitis)
Some chemo drugs can cause lung irritation or inflammation.
Report immediately if you experience:
Persistent dry cough
Shortness of breath
Chest discomfort
Fever without another clear cause
Severe Neuropathy (Nerve Damage)
Peripheral neuropathy can worsen over time if not addressed early.
Report urgently if you notice:
Trouble walking or frequent falls
Significant numbness (can’t feel the floor)
Severe pain in hands/feet
Difficulty holding objects or buttoning clothing
Dose adjustment may prevent symptoms from becoming permanent.
Kidney or Liver Problems
Some chemo medications can affect the kidneys or liver.
Tell your doctor if you have:
Yellowing of skin or eyes (jaundice)
Dark urine or pale stools
Severe itching
Persistent nausea
Swelling, decreased urination, or pain in the side/back
When to Seek Urgent Help
Call your cancer center immediately or go to emergency care if you have:
Fever ≥ 38°C (100.4°F)
Difficulty breathing
Chest pain
Uncontrolled bleeding
Severe weakness, confusion, or fainting
Persistent vomiting or severe diarrhea
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