Does HUMIRA cause diarrhea? A comprehensive guide to gastrointestinal side effects

October 14, 2025 •

3 min read

Clinical trial data indicate that diarrhea and other gastrointestinal issues are among the common side effects reported by patients taking Humira (adalimumab). Understanding if HUMIRA causes diarrhea is crucial for those on this therapy, especially when differentiating a side effect from a symptom of their underlying condition.

Quick Summary

Humira (adalimumab) can cause diarrhea and other gastrointestinal side effects, such as abdominal pain and nausea. This is often a mild reaction, but can also signal a serious infection or disease flare-up in patients. There are effective management strategies and alternative treatments.

Key Points

Common Side Effect: Diarrhea is reported by 1–10% of patients taking Humira and is typically mild.
Distinguishing Symptoms: For patients with inflammatory bowel disease, it can be difficult to tell if diarrhea is a side effect of Humira or a flare-up of their condition.
Infection Risk: As an immunosuppressant, Humira increases the risk of infection, and persistent or severe diarrhea can be a sign of a serious infection.
Management: Mild cases can often be managed through increased hydration and dietary changes, such as eating bland foods.
Immediate Medical Contact: Severe, persistent, or bloody diarrhea, especially with fever, requires immediate medical attention.
Alternative Options: Other biologics and treatments are available for patients who experience unmanageable side effects from Humira.

Understanding Humira's Effect on the Gastrointestinal System

Humira, with the active ingredient adalimumab, is a biologic medication that works by targeting tumor necrosis factor (TNF), a protein that causes inflammation in the body. It is used to treat a variety of autoimmune conditions, including Crohn's disease, ulcerative colitis, rheumatoid arthritis, and psoriatic arthritis. While it effectively reduces inflammation, its immunosuppressive nature can lead to side effects, including impacts on the gastrointestinal (GI) system.

How Common is Diarrhea with Humira?

According to information on Humira's side effects, diarrhea is a recognized and relatively common adverse event. While exact rates can vary based on the specific clinical trial and treated condition, the incidence is reported to occur in 1% to 10% of patients. Alongside diarrhea, patients may also experience other common GI issues such as nausea, vomiting, and abdominal pain. For most, these are mild and may resolve with continued use, but they can be distressing and disruptive for some.

Recognizing Humira-Related Diarrhea vs. Disease Symptoms

For patients taking Humira for inflammatory bowel diseases (IBD) like Crohn's or ulcerative colitis, distinguishing between a drug side effect and a flare-up of their underlying condition can be challenging. An increase in diarrhea could be caused by either. Healthcare providers will need to consider the full context of the patient's symptoms, recent lab results, and overall disease activity to make a proper diagnosis. Symptoms of an infection, which can also cause diarrhea, need to be ruled out.

Managing Diarrhea While on Humira

If you experience diarrhea while on Humira, there are several steps you can take to manage it, but it is essential to consult your healthcare provider first.

Stay Hydrated: The most important step is to prevent dehydration, especially if the diarrhea is persistent. Drink plenty of clear fluids, such as water, broth, and electrolyte-replenishing drinks.
Adjust Your Diet: Consider a diet of bland, low-fiber foods, often referred to as the BRAT diet (bananas, rice, applesauce, toast), which can help firm up stools. Avoid dairy products, spicy food, high-fat meals, and caffeine, as these can aggravate symptoms.
Practice Food Safety: Since Humira suppresses the immune system, the risk of foodborne illness increases. To minimize this risk, avoid raw or undercooked animal products, wash hands frequently, and cook food thoroughly.
Discuss Medications: Over-the-counter anti-diarrheal medications can be used, but only with the approval of your doctor, as they may interact with other medications or mask a more serious issue.

When to Seek Medical Attention

While mild diarrhea may not be an immediate cause for alarm, certain signs and symptoms warrant immediate medical contact. You should call your doctor if you experience any of the following:

Diarrhea that is persistent or severe.
Signs of infection, such as fever, sweats, or chills.
Bloody or black, tarry stools.
Excessive fatigue or extreme weakness.
Significant abdominal pain or cramping.
Symptoms of dehydration, including extreme thirst, dark urine, or dizziness.

Comparison of Humira and Alternative Medications

For patients who cannot tolerate the side effects of Humira, including diarrhea, other treatment options are available. These alternatives often work through different mechanisms and may have different side-effect profiles. It's important to discuss all options with your doctor.


Medication (Class)	Mechanism of Action	Common Side Effects	Potential GI Side Effects
Humira (adalimumab) (TNF Inhibitor)	Blocks the TNF-alpha protein.	Injection site reactions, upper respiratory infections, headache.	Nausea, diarrhea, abdominal pain.
Remicade (infliximab) (TNF Inhibitor)	Also blocks the TNF-alpha protein.	Infusion-related reactions (fever, chills), upper respiratory infections.	Nausea, abdominal pain, diarrhea.
Xeljanz (tofacitinib) (JAK Inhibitor)	Inhibits Janus Kinase (JAK) enzymes.	Upper respiratory infection, headache, rash.	Diarrhea, nausea, vomiting.
Stelara (ustekinumab) (IL-12/23 Inhibitor)	Blocks the IL-12 and IL-23 proteins.	Upper respiratory infection, headache, fatigue.	Nausea, vomiting.
Orencia (abatacept) (T-cell Modulator)	Modulates T-cell activation.	Nausea, headache, infections.	Nausea.

Conclusion

Diarrhea is a possible, and sometimes common, side effect for patients taking Humira. While it is often mild and manageable, it is essential for patients to monitor their symptoms closely, particularly those who also have an underlying inflammatory bowel disease, which makes symptom attribution more complex. The immunosuppressive nature of Humira means that persistent or severe diarrhea could signal a more serious infection, necessitating prompt medical evaluation. Patients who experience troublesome or unmanageable diarrhea should discuss their concerns with their healthcare provider to explore management strategies or consider potential alternative treatments. A balanced approach involving communication with your medical team, proper hydration, and dietary management can help minimize the impact of this side effect. Learn more about Humira by visiting the official Humira website.

Frequently Asked Questions

Based on clinical data, diarrhea is considered a common side effect of Humira, reported in 1% to 10% of patients.

While often mild, persistent or severe diarrhea, especially with fever or other signs of infection, should be reported to a doctor immediately, as it could indicate a serious infection.

Yes, Crohn's and ulcerative colitis both cause diarrhea. Determining the cause requires medical evaluation, as it could be a flare-up of your condition or a drug side effect.

For mild cases, staying hydrated and adjusting your diet by consuming bland, low-fiber foods can help. Always discuss your symptoms with your doctor.

Never stop taking Humira without consulting your healthcare provider. They will evaluate your symptoms and determine the appropriate course of action.

Other TNF inhibitors like Remicade and Enbrel also list gastrointestinal side effects, including diarrhea, although individual reactions vary.

While no specific food interactions are noted, avoiding raw or undercooked foods and practicing good food safety is recommended to minimize infection risk while on immunosuppressant therapy.