How to stop diarrhea from immunotherapy? A comprehensive guide to management

October 14, 2025 •

4 min read

Studies show that immune-related adverse events (irAEs), including diarrhea and colitis, can affect a significant percentage of patients receiving immunotherapy. Understanding how to stop diarrhea from immunotherapy? is crucial for managing these side effects effectively and ensuring treatment continuity. The first step is always to communicate with your oncology care team.

Quick Summary

Management of immunotherapy-induced diarrhea ranges from supportive care and medication for mild cases to corticosteroids and advanced biologics for severe immune-mediated colitis. Strategies depend on severity, emphasizing early intervention and medical supervision.

Key Points

Report Immediately: Any change in bowel movements, especially more than three loose stools per day, should be reported to your oncology care team immediately.
Stay Hydrated: Drink plenty of clear fluids and broths to replace lost electrolytes and prevent dehydration, which is a significant risk with diarrhea.
Modify Diet: Stick to a bland, low-fiber, and low-fat diet while avoiding trigger foods and drinks like caffeine and spices.
Consult Before Medication: Never take over-the-counter loperamide without consulting your doctor, as an infectious cause must be ruled out first.
Corticosteroids for Severity: For moderate or severe diarrhea (Grade 2+), systemic corticosteroids like prednisone are the first-line treatment to reduce inflammation.
Biologics are Next: If steroids are ineffective, biologics such as infliximab or vedolizumab are introduced to target the inflammation more specifically.
Early Intervention Mitigates Risks: Prompt treatment is critical to prevent the progression of colitis to severe complications and to safely manage side effects.

Recognizing and Reporting Immunotherapy-Induced Diarrhea

Immunotherapy activates the body's immune system to fight cancer, but this can sometimes lead to unintended inflammation in healthy organs. When this occurs in the gastrointestinal tract, it is known as immune-mediated colitis (IMC), with diarrhea being a primary symptom. Diarrhea severity is graded clinically, which dictates the appropriate treatment path. Prompt communication with your oncology care team is essential to distinguish IMC from other causes of diarrhea and to initiate timely intervention.

Managing Mild (Grade 1) Diarrhea

Mild diarrhea, defined as an increase of 1 to 3 loose stools per day over baseline, can often be managed with supportive care while continuing immunotherapy. The primary focus is on symptom relief and preventing dehydration.

Supportive Care and Dietary Adjustments

Hydration: Drink plenty of fluids to replace lost water and electrolytes. Options include water, clear broth, and electrolyte-rich sports drinks.
Bland Diet: Adopt a low-fiber, low-fat, and lactose-free diet. Bland foods like the BRAT diet (bananas, rice, applesauce, toast) are often recommended temporarily.
Avoid Irritants: Steer clear of spicy foods, caffeine, alcohol, raw vegetables, and nuts, which can exacerbate symptoms.
Small, Frequent Meals: Eating smaller portions more frequently throughout the day can be less taxing on the digestive system.

Antidiarrheal Medication (Loperamide)

Under medical supervision, over-the-counter antidiarrheals like loperamide (Imodium®) can be used for low-grade diarrhea, but only after an infectious cause has been ruled out by your healthcare provider. Taking loperamide without professional guidance can mask underlying infections, so consultation is mandatory.

Treating Moderate to Severe (Grade 2-4) Diarrhea

Moderate-to-severe diarrhea, indicated by a significant increase in loose stools, abdominal pain, or blood, requires more intensive management.

Holding Immunotherapy and Infection Workup

For moderate (Grade 2) or more severe cases, the immunotherapy regimen is typically held to prevent further immune-mediated damage. A full infectious workup, including a stool test for Clostridium difficile, is performed immediately to ensure the correct diagnosis and treatment path.

Corticosteroids: The First-Line Intervention

For confirmed IMC, corticosteroids are the standard first-line treatment to suppress the immune system and reduce intestinal inflammation.

Prednisone: Moderate cases may start with an oral steroid, such as prednisone.
Methylprednisolone: Severe cases may require hospitalization for intravenous administration of higher-dose corticosteroids.
Tapering: Once symptoms resolve, the steroid dose is slowly tapered over a period of 4 to 8 weeks to prevent recurrence.

Advanced Biologics for Steroid-Refractory Colitis

For patients whose symptoms do not improve with corticosteroids, treatment is escalated to biologic therapies. Early introduction of these agents can lead to better outcomes and shorter hospital stays.

Infliximab: This anti-tumor necrosis factor (TNF)-α antibody is effective for many steroid-refractory colitis cases.
Vedolizumab: As a gut-specific anti-integrin agent, vedolizumab can be an option for patients who fail to respond to or cannot tolerate infliximab, offering a more localized effect on the gut inflammation.
Fecal Microbiota Transplantation (FMT): In highly refractory cases where standard treatments have failed, FMT has shown promise in some reports for restoring a healthy gut microbiome.

Comparison of Treatment Strategies


Treatment Strategy	Indication	Mechanism of Action	Response Timeframe	Key Considerations
Supportive Care (Diet & Hydration)	Mild diarrhea (Grade 1)	Replaces fluids/electrolytes, minimizes bowel irritation	Short-term relief, symptom-dependent	Should not be used alone for moderate-to-severe cases; hydration is crucial at all stages.
Loperamide	Mild diarrhea (Grade 1), post-consultation	Slows down intestinal motility	Rapid	Requires careful medical supervision to rule out infection.
Corticosteroids (Prednisone, Methylprednisolone)	Moderate to severe (Grade 2-4) colitis	Broad systemic immunosuppression to reduce inflammation	Days to weeks	Risk of systemic side effects (e.g., infections, hyperglycemia).
Budesonide (Local Steroid)	Mild-to-moderate colitis, transitioning off systemic steroids	Localized anti-inflammatory effect in the gut	Days to weeks	Lower risk of systemic side effects compared to oral prednisone.
Infliximab	Steroid-refractory colitis	Blocks TNF-α, a potent inflammatory cytokine	Days	Screening for latent infections (e.g., TB) is needed before use.
Vedolizumab	Infliximab-refractory or intolerant colitis	Prevents T-cell migration to the gut (gut-selective)	Weeks (slower onset)	Lower systemic infection risk compared to infliximab.

Conclusion: Proactive Management is Key

Immunotherapy-induced diarrhea and colitis require a proactive and tailored management strategy based on the severity of symptoms. Early reporting of symptoms to your oncology care team is paramount, as is the immediate initiation of an appropriate treatment plan. While supportive care and antidiarrheals are effective for mild cases, moderate and severe cases necessitate the use of systemic corticosteroids, and potentially biologic agents, to control inflammation. Collaborative care involving oncologists, gastroenterologists, and dietitians is essential to navigating this side effect successfully and ensuring patients can continue their vital cancer treatment safely. For reliable information on cancer-related side effects, consider resources from reputable organizations such as the National Cancer Institute.

Frequently Asked Questions

Immunotherapy-induced diarrhea is most often caused by immune-mediated colitis (IMC), a condition where the activated immune system mistakenly attacks the healthy cells of the gastrointestinal tract, leading to inflammation and diarrhea.

Contact your healthcare provider if you have more than 3 watery stools per day, notice blood or mucus in your stool, experience severe abdominal pain, or cannot keep liquids down for more than 24 hours.

Only after consulting your healthcare provider. It is crucial to rule out infectious causes like Clostridium difficile before taking any antidiarrheal medication, as it could be harmful in some instances.

Helpful changes include eating small, frequent meals; sticking to bland, low-fiber, low-fat foods (like bananas, rice, and toast); and avoiding spicy, high-fiber, caffeinated, and alcoholic items.

If mild diarrhea progresses to moderate or severe, your doctor will likely pause the immunotherapy and start treatment with systemic corticosteroids, such as prednisone, to reduce intestinal inflammation.

If colitis is steroid-refractory, biologic therapies like infliximab are typically used next. For cases resistant to infliximab, a gut-specific biologic called vedolizumab may be considered.

Restarting immunotherapy is a decision made by your care team after careful evaluation. It is generally considered safe once symptoms have resolved to grade 1 or less and after a controlled taper of corticosteroids.