C. diff treatment centers on targeted antibiotics that kill the bacteria while sparing the rest of your gut, followed by strategies to prevent the infection from coming back. “CD” most commonly refers to Clostridioides difficile infection (CDI), though it can also stand for Crohn’s disease. This article covers both, starting with C. diff, since that’s what most people searching for “CD treatment” need to know.
First-Line Antibiotics for C. Diff
The current recommended first-line treatment for an initial C. diff episode is fidaxomicin, a narrow-spectrum antibiotic that targets C. diff while leaving more of your healthy gut bacteria intact. It’s taken twice daily for 10 days. Vancomycin, taken orally four times daily for 10 days, remains a well-accepted alternative. Both are taken by mouth, not through an IV, because the infection lives in the colon and the drugs need to reach it directly.
Fidaxomicin has a meaningful edge when it comes to preventing recurrence. In a large trial published in the New England Journal of Medicine, 15.4% of patients treated with fidaxomicin had their infection return, compared to 24% of those treated with vancomycin. That difference matters because recurrence is the most frustrating part of dealing with C. diff: roughly 1 in 5 people who recover from an initial episode will get it again.
How Severity Changes the Approach
Doctors classify C. diff infections as non-severe, severe, or fulminant based on a few key markers. A white blood cell count of 15,000 or higher, or kidney function that has worsened significantly from baseline, bumps the infection into the severe category. Fulminant cases involve dangerously low blood pressure, a condition called toxic megacolon (where the colon swells and stops working), or signs of shock.
For non-severe and severe cases, the same oral antibiotics apply, though severe cases are monitored more closely. Fulminant infections typically require hospital care and may involve surgical intervention if the colon is at risk of rupturing.
Treating Recurrent C. Diff
When C. diff comes back, the treatment strategy shifts. Fidaxomicin is again preferred, but the dosing schedule often changes. An extended-pulsed regimen gives the full dose twice daily for the first five days, then drops to once every other day through day 25. This tapering approach helps clear the bacteria while giving healthy gut flora a chance to reestablish. A tapered and pulsed vancomycin course is an acceptable alternative for a first recurrence.
For people dealing with a second or third recurrence, the options expand beyond antibiotics alone. This is where microbiome-based therapies come in.
Microbiome Restoration Therapies
Fecal microbiota transplant (FMT) introduces healthy donor bacteria into the gut to rebuild the microbial community that C. diff has disrupted. The procedure can be delivered through a colonoscopy or through the upper digestive tract. Whether the donor stool is fresh or frozen doesn’t appear to affect outcomes, and both delivery routes work similarly well.
FMT works best when the infection has partially responded to antibiotics first. In patients who had some initial improvement from antibiotics, FMT achieved a 100% success rate in one study. For truly refractory cases, where the infection showed no response to a week of antibiotic therapy, the success rate dropped to about 71%. The takeaway: FMT is a powerful tool, but it works with antibiotics, not as a replacement for them.
The FDA has also approved an oral capsule product called VOWST for preventing recurrence in adults who have already completed antibiotic treatment for recurrent C. diff. It contains purified bacterial spores from donor stool and is taken as four capsules daily for three consecutive days, on an empty stomach. A bowel preparation with magnesium citrate is required the day before starting. VOWST is specifically for preventing recurrence, not for treating an active infection.
Preventing Recurrence With Antibody Therapy
Bezlotoxumab is a single-dose intravenous infusion given alongside antibiotic treatment in patients considered high risk for recurrence. It works by neutralizing one of the two main toxins that C. diff produces, blocking the damage that toxin causes to intestinal cells. It doesn’t kill the bacteria itself, so it’s always used together with antibiotics, never alone. It’s given once, as a 60-minute infusion, during the course of antibiotic treatment.
How C. Diff Is Diagnosed
If you’re reading this because you suspect you have C. diff, diagnosis typically involves a stool sample tested in stages. The first screening test checks for an antigen the bacteria produces, which catches 94 to 96% of true cases. If that’s positive, a toxin test looks for the harmful substances the bacteria releases, with a specificity of 99%, meaning false positives are extremely rare. A genetic (PCR) test may be added as a tiebreaker when results are unclear, combining for an overall sensitivity of 91 to 96%.
Testing is only done on loose, watery stool. Formed stool should not be tested, because many people carry C. diff in their gut without being sick, and a positive result on a healthy stool sample would lead to unnecessary treatment.
Diet During C. Diff Treatment
What you eat during treatment can influence recovery. Research in animal models shows that high-fat, low-fiber diets increase C. diff toxin levels and shift gut bile acids toward compounds that actually help the bacteria germinate. Fiber, particularly pectin, has shown the opposite effect in some models, reducing intestinal inflammation and toxin-related tissue damage. Short-chain fatty acids, which your gut bacteria produce when they ferment fiber, also appear to help the immune system fight the infection.
In practical terms, this means leaning toward easily digestible, lower-fat foods and including soluble fiber as your gut tolerates it. During active diarrhea, bland foods like bananas, rice, applesauce, and toast are easier on the digestive system. As symptoms improve, gradually reintroducing a varied, fiber-rich diet supports the regrowth of healthy gut bacteria. One concern that has been investigated, the sugar trehalose (found in some processed foods), does not appear to worsen C. diff infection based on current evidence.
If “CD” Means Crohn’s Disease
Crohn’s disease treatment depends on severity and which part of the digestive tract is affected. Mild to moderate Crohn’s involving the small intestine or right colon is typically managed with budesonide, a steroid that works locally with fewer body-wide side effects than traditional steroids. Active Crohn’s in the colon often starts with sulfasalazine to induce remission, then transitions to a related maintenance drug.
When the disease doesn’t respond to these first-line options, immunosuppressive drugs that dial down the overactive immune response become the next step. For moderate to severe Crohn’s that resists initial therapies, biologic medications that block specific inflammatory proteins are the standard escalation. These are given by infusion or injection and target the immune pathways driving intestinal inflammation. Maintenance therapy with immunosuppressants is used long-term to keep the disease in remission.
Severe or fulminant Crohn’s, which can involve intestinal obstruction or deep ulceration, often requires hospitalization and may eventually need surgery to remove damaged sections of bowel. The overall strategy in Crohn’s treatment is to control inflammation early and aggressively enough to prevent permanent intestinal damage, then find the lowest level of medication that keeps symptoms quiet.