Neomycin: Sibo Explained

Neomycin is a broad-spectrum antibiotic that is commonly used in the treatment of a variety of bacterial infections. It belongs to the aminoglycoside class of antibiotics, which work by inhibiting protein synthesis in bacteria, thereby preventing their growth and multiplication. This article provides an in-depth exploration of Neomycin, its role in treating Small Intestinal Bacterial Overgrowth (SIBO), and the various aspects surrounding its use.

Small Intestinal Bacterial Overgrowth, or SIBO, is a condition where there is an excessive amount of bacteria in the small intestine. This can lead to a variety of symptoms, including bloating, diarrhea, abdominal pain, and malnutrition. Treatment of SIBO often involves the use of antibiotics like Neomycin to reduce the bacterial population in the small intestine.

Understanding Neomycin

Neomycin was first discovered in 1949 by the American microbiologist Selman Waksman. It is produced by the bacterium Streptomyces fradiae and is named after the New Jersey laboratory where it was first isolated, the Neo (New) Jersey lab. Neomycin is a complex molecule that contains several sugar groups attached to a central aglycone structure. This complex structure allows it to bind to bacterial ribosomes and inhibit protein synthesis.

Neomycin is often used in combination with other antibiotics to treat a variety of infections. It is commonly used in topical creams and ointments to treat skin infections, as well as in eye and ear drops to treat infections in these areas. However, it is also used orally to treat gastrointestinal infections, including SIBO.

Pharmacokinetics of Neomycin

When taken orally, Neomycin is poorly absorbed into the bloodstream, with less than 3% of the dose reaching systemic circulation. This is advantageous in the treatment of gastrointestinal infections, as it allows high concentrations of the antibiotic to remain in the gut where it can act on the bacteria. The majority of the drug is excreted unchanged in the feces.

Due to its poor absorption, systemic side effects of Neomycin are rare. However, when they do occur, they can be serious and include ototoxicity (damage to the ear) and nephrotoxicity (damage to the kidneys). These side effects are more common with prolonged use or high doses of the drug.

Mechanism of Action

Neomycin works by binding to the 30S subunit of bacterial ribosomes, which are the structures that synthesize proteins. By binding to the ribosome, Neomycin interferes with the process of protein synthesis, preventing the bacteria from growing and multiplying. This bactericidal action is what makes Neomycin effective in treating bacterial infections.

It's important to note that Neomycin is a broad-spectrum antibiotic, meaning it is effective against a wide range of bacteria. This includes both gram-positive and gram-negative bacteria, as well as some species of mycobacteria. However, some bacteria have developed resistance to Neomycin, which can limit its effectiveness.

Neomycin and SIBO

SIBO is a condition characterized by an overgrowth of bacteria in the small intestine. This can disrupt the normal function of the gut and lead to a variety of symptoms. The treatment of SIBO often involves the use of antibiotics to reduce the bacterial population in the small intestine, and Neomycin is one of the antibiotics commonly used for this purpose.

Neomycin is particularly effective in treating SIBO due to its poor absorption from the gut. This allows high concentrations of the drug to remain in the small intestine where it can act on the bacteria. Furthermore, Neomycin's broad-spectrum activity means it can target a wide range of bacteria, which is beneficial in treating SIBO as the condition often involves multiple species of bacteria.

Effectiveness of Neomycin in Treating SIBO

Several studies have demonstrated the effectiveness of Neomycin in treating SIBO. In one study, 80% of patients with SIBO who were treated with Neomycin experienced a significant reduction in their symptoms. In another study, Neomycin was found to be as effective as the antibiotic rifaximin in treating SIBO.

However, it's important to note that while Neomycin can be effective in treating SIBO, it is not a cure for the condition. SIBO often recurs after treatment, and may require repeated courses of antibiotics. Furthermore, the use of antibiotics can disrupt the normal gut flora, which can lead to other problems such as antibiotic-associated diarrhea.

Side Effects and Precautions

While Neomycin is generally well-tolerated, it can cause side effects in some people. These can include nausea, vomiting, and diarrhea. More serious side effects, such as ototoxicity and nephrotoxicity, are rare but can occur with prolonged use or high doses of the drug.

Due to the risk of ototoxicity and nephrotoxicity, Neomycin should be used with caution in patients with pre-existing kidney disease or hearing problems. It should also be used with caution in elderly patients, as they may be more susceptible to these side effects. Furthermore, Neomycin can interact with certain other medications, so it's important to inform your doctor of any other drugs you are taking before starting treatment with Neomycin.


Neomycin is a powerful antibiotic that plays a crucial role in the treatment of SIBO. Its ability to remain concentrated in the gut, combined with its broad-spectrum activity, make it an effective choice for reducing the bacterial overgrowth associated with this condition. However, like all medications, it must be used judiciously and under the guidance of a healthcare professional to minimize the risk of side effects and ensure the best possible outcome for the patient.

As our understanding of SIBO continues to evolve, so too will our approach to treating it. While Neomycin currently plays a key role in the management of this condition, ongoing research may lead to the development of new treatments that are even more effective and have fewer side effects. As always, the goal is to improve the quality of life for patients living with this challenging condition.

Back to blog

Keto Paleo Low FODMAP Cert, Gut & Ozempic Friendly

1 of 12

Keto. Paleo. No Digestive Triggers. Shop Now

No onion, no garlic – no pain. No gluten, no lactose – no bloat. Low FODMAP certified.

Stop worrying about what you can't eat and start enjoying what you can. No bloat, no pain, no problem.

Our gut friendly keto, paleo and low FODMAP certified products are gluten-free, lactose-free, soy free, no additives, preservatives or fillers and all natural for clean nutrition. Try them today and feel the difference!