Healing Intestinal Methanogen Overgrowth (IMO) : My Personal Protocol After Cancer

Healing my gut after cancer and transplant has been a journey.

My Intestinal Methanogen Overgrowth Journey: What Worked, What Didn’t, and What I Wish I’d Done Differently

In my Complete Guide to IMO and SIBO, I gave a no-nonsense breakdown of what these conditions are and why they’re a nightmare for cancer survivors. But in this article? I’m getting personal. This is my real-life, totally biased, trial-and-error experience—what actually worked for me, what was a waste of time, and the things I wish I had done differently from the start.

How It All Started: Post-Transplant Gut Chaos

I knew something was off right after stopping the antibiotics from my genetically modified T-cell transplant. After six months of weekly antibiotics, I had been religiously taking probiotics and eating fermented foods, but they were no match for what the antibiotics had done to my gut.

Chemo, radiation, more chemo, and the transplant had already obliterated my microbiome, and on top of that, my gut motility was completely shot.

So when my digestion started spiraling post-transplant, I didn’t need a test to tell me—I knew it was IMO.

It Had to be IMO

IMO (Intestinal Methanogen Overgrowth) is common in IBS-C and follows a relentless cycle. You feel fine for a couple of weeks, then suddenly, it’s like a full-body bacterial attack—energy crashes, digestion stalls, and even keeping food down feels impossible. Eventually, you go to the bathroom, get brief relief, and then… it all starts again. Constipation, flu-like symptoms, repeat.

Sound familiar? You’re not imagining it. A Cedars-Sinai study confirmed that methane overgrowth is directly linked to severe constipation (Healio). Methane gas slows everything down, creating a traffic jam with no exit—and no amount of fiber or water seems to get things moving.

SIBO, on the other hand, follows a similar pattern of stomach pain but with one key difference—diarrhea instead of constipation.

There Had to Be Another Way… Or So I Thought

At this point, I couldn’t stomach the thought of taking more antibiotics. I mean… wasn’t that what got me here in the first place? The idea of wiping out even more bacteria felt like a terrible idea.

So, I did what any desperate, determined, and slightly unhinged person would do—I went full mad scientist mode for an entire year (yes, a YEAR), throwing every natural protocol at my gut to see what would stick. A lot of people swear by Low FODMAP or elimination diets to fix SIBO and IMO. And while I think they can help for short-term symptom relief, I also knew that gut health is all about diversity—and overly restricting foods can actually make things worse in the long run.

Research backs this up. A healthy gut microbiome thrives on a wide variety of fibers and plant foods, not just the handful of “safe” foods you’re left with on restrictive diets (Verywell Health). So while I temporarily cut down on certain fermentable foods (to stop the bloating from hell), I didn’t go all-in on elimination diets. Instead, I focused on gut motility, bacterial balance, and repairing my gut lining.

And Here Comes the… Or So I Thought

A year later, despite all my effort, I was still stuck. I knew the science, the supplements, the protocols—but nothing was changing. Frustrated, I finally called my doctor.

She ordered a breath test, and—big surprise—I had IMO. Textbook, undeniable, methane-producing IMO. She prescribed me two antibiotics for two weeks. I hated the idea. After everything I’d learned, I was convinced antibiotics would make things worse. But at that point, I felt so awful, I figured… what do I have to lose?

The antibiotics were brutal. My immune system crashed, and within days of finishing, I got the flu from hell, followed by shingles. It was a miserable month.

But then… something shifted. For the first time in forever, I felt normal. No bloating. No gut pain. And in that moment, I was so mad at myself for waiting so long.

I had spent a year avoiding antibiotics, terrified they’d wreck my gut even more. But here I was, finally feeling human again—and all I could think was, why didn’t I just do this sooner?

The Problem with Doctors and Naturopaths

And here’s the issue… (the one I seem to rant about constantly on this blog). Traditional medicine and naturopathy refuse to work together, leaving most people with only half the solution—at best.

If I had taken antibiotics without understanding that my post-transplant antibiotic course and poor motility were the root causes of my IMO, I would have relapsed within months. And if I had stubbornly believed I could heal naturally—without acknowledging just how bad things had gotten—I’d probably still be stuck in the same miserable cycle.

If I’m remembered for anything, let it be this: I believe in the power of both. You can’t just take a prescription and expect long-term healing, and you can’t just drink herbal tea and hope for a miracle. You need both.

My Protocol for IMO

Stepping off my soapbox—let’s get into it. I say "managing" IMO for a reason—gut motility issues don’t just disappear, especially after cancer treatment. If your gut has taken a hit, motility may be a lifelong struggle.

Managing IMO isn’t just about killing the overgrowth—it’s about making sure it stays gone and that your gut actually functions properly. If you only fix one piece of the puzzle, you’ll end up right back where you started.

Let’s get into it.

The Three-Part Approach to Managing IMO

First, I want to note that to some this will seem daunting. I admit, it’s not ideal, but that’s the reality of what our bodies go through. I try not to let it consume my mind much and honestly after so long, it just becomes routine with very little effort.

The Three-Part Approach to Managing IMO

1. Fix Motility – I believe this is one of the most overlooked root causes of IMO. When motility slows down, bacteria have more time to ferment in the small intestine, leading to methane overgrowth. If you don’t address the underlying motility issue, IMO is likely to return even after treatment.

2. Kill the Overgrowth – Eliminate methane-producing archaea.

3. Keep It from Coming Back – Create an environment where the archaea can’t thrive. This means dietary tweaks, gut support (probiotics, but not too soon), and meal spacing to prevent regrowth.

You need all three. Fix motility, kill the overgrowth, and prevent its return—otherwise, you’re just setting yourself up for relapse.

Motility:

1. Water - 80 oz minimum, ideally 140 oz. Since water can be really hard to drink when you already have stomach pain, I start my day on an empty stomach consuming 40 oz of water. I just force myself to drink it- no nursing of the water, I get it down quickly. When you have motility issues food can take longer to digest, so I don’t drink water with my food, but rather between meals on an empty stomach.

2. Motility supplements

   1. MotilPro Needs to be taken daily. Adjust serving size as needed, I take 2.

   2. Intestinal Movement Formula - This is my ride or die. I often suggest this to people who are having temporary constipation from chemotherapy or other medical issues. I wouldn’t use this for a prolonged period, but when I’m traveling I take half a dose nightly.

   3. 5-HTP (100 mg)- I take this for my mood, I’ve taken it for 10 years. When I don’t take it, I notice a big difference in how I feel. However, 5-HTP can also increase serotonin in the gut (it’s also in MotilPro). This study dives further into the link between motility and 5-HTP.

Killing the Overgrowth:

1. Rifaximin - Taken for 2 weeks. I’ve had three cancer diagnoses and a transplant and this is the only drug that has ever been denied by my insurance. I had to appeal it and ended up getting it covered.

2. Neomycin - Taken for 2 weeks

Maintenance:

Here’s the fun part, maintaining it all…

1. Berberine - 500 mg (1 capsule at night). While IMO is harder to treat than SIBO, this study showed berberine to be just as effective as Rifaximin in treating SIBO, with a 46% response rate for berberine compared to 36% for Rifaximin.

2. Metagenics Candibactin AR - 1 capsule at night. This study found that oregano oil reduced methane production by 87%, making it a great choice for IMO management.

3. Atrantil - 2 capsules for maintenance. I discovered this supplement on Reddit, where the IMO community rated it highly, and I have to agree—it helps keep symptoms in check.

4. Scram - I take this intermittently a few times a year for maintenance, rather than as suggested (which is a 10 pill per night course). It’s strong—each capsule contains 500 mg, which is much higher than other brands. Taking three capsules puts you at 1,500 mg, so be mindful of dosing!

The relapse rate for IMO and SIBO after antibiotic treatment is 40-50%, so I won’t pretend my stomach never acts up. While I was willing to take antibiotics the first time, I now manage flare-ups by increasing my maintenance supplements and slightly altering diet (see below).

Dietary Changes

Before cancer, my diet was pretty limited, but I’ve since learned that lack of diversity can actually harm gut health rather than help it. Now, I make a point to rotate my foods each week instead of relying on the same five “safe” options. I focus on whole foods, avoid refined sugar, and cook most of my meals from scratch, keeping processed foods to a minimum.

When my stomach acts up, I avoid snacking and make sure to wait at least 3-4 hours between meals to allow my Migrating Motor Complex (MMC) to function properly. The MMC is the gut’s built-in housekeeping system, responsible for clearing out bacteria, undigested food, and waste from the stomach and small intestine. But here’s the key—it only activates during fasting. Constant snacking or eating small meals throughout the day shuts it down, preventing proper gut clearance.

Despite how crucial the MMC is for gut health, not a single doctor has ever mentioned it to me. Yet, as someone managing IMO, I’ve found it to be one of the most important factors in getting relief.

Final Thoughts: Finding What Works for You

If there’s one thing I’ve learned from this journey, it’s that managing IMO isn’t a one-size-fits-all process. What worked for me took trial, error, frustration, and a lot of stubborn determination.

I wish I had figured things out sooner. I wish I had known about motility issues, the importance of the MMC, and that antibiotics—while not ideal—helped me finally break the cycle. But more than anything, I wish I had known that long-term relief isn’t about finding one magic solution—it’s about layering the right tools together.

Managing IMO is an ongoing process. Some days, I feel completely normal. Other days, I get a flare-up and have to adjust. But the difference now? I know what to do. I have the tools, the knowledge, and the experience to keep things in check without spiraling.

If you’re dealing with IMO, advocate for yourself. Push for testing, experiment with what works for your body, and don’t let doctors brush you off. Because at the end of the day, no one else is going to figure this out for you.

You’re not alone in this. And trust me—relief is possible.