Metronidazole as a Survival Antibiotic


Antibiotics are an important part of any medical arsenal in tough times. Many infections easily treated today would possibly be life-threatening in an off-grid survival setting. Indeed, if such a thing occurred, you can bet that these drugs would no longer be produced. There would be a lot of otherwise avoidable deaths due to simple cuts that become infected or dehydration from diarrheal disease. We only have to look at mortality statistics from pre-antibiotic times like the Civil War to know that this is true. More soldiers died then from infectious disease that from bullets or shrapnel.



This article is part of a series on antibiotics and their use in survival settings. Today we’ll talk about an antibiotic that would be useful to deal with some organisms that can cause a number of major problems. Metronidazole (aquatic equivalent: Fish-Zole) 250mg is an antibiotic in the Nitroimidazole family that is used primarily to treat infections caused by anaerobic bacteria and protozoa.

“Anaerobes” are bacteria that do not depend on oxygen to live. “Protozoa” have been defined as single-cell organisms with animal-like behavior. Many can propel themselves randomly from place to place by the means of a “flagellum”; a tail-like “hair” they whip around that allows them to move.



Giardia (Protozoal Parasite)

The antibiotic Metronidazole works by blocking some of the functions within bacteria and protozoa, thus resulting in their death. It is better known by the U.S. brand name Flagyl and usually comes in 250mg and 500mg tablets. Metronidazole (Fish-Zole) is used in the treatment of these bacterial diseases:



• Diverticulitis (an intestinal infection seen in older individuals)
• Peritonitis (an inflammation of the abdominal lining due to a ruptured appendix, ruptured cysts, and other causes)
• Certain pneumonias (lung infections)
• Diabetic foot ulcer infections
• Meningitis ( an infection of the spinal cord and brain lining)
• Bone and joint infections
• Colitis due to a bacterial species known as Clostridia (sometimes caused by taking Clindamycin!)
• Endocarditis (a heart infection)
• Bacterial vaginosis (a very common vaginal infection)
• Pelvic inflammatory disease (an infection in women which can lead to abscesses, often in combination with other antibiotics)
• Uterine infections (especially after childbirth and miscarriage)
• Dental infections (sometimes in combination with amoxicillin)
• H. pylori infections (a bacteria that causes peptic ulcers)
• Some skin infections

And those are just the bacterial infections that metronidazole can deal with. It also works with these protozoal infections:

• Amoebiasis: dysentery caused by Entamoeba species (contaminated water/food)
• Giardiasis: infection of the small intestine caused by Giardia Species (contaminated water/food)
• Trichomoniasis: vaginal infection caused by parasite which can be sexually transmitted

Amoebiasis and Giardiasis can be caught from drinking what appears to be the purest mountain stream water, and these infections are seen right here in the Great Smoky Mountains and elsewhere. Never fail to sterilize all water, regardless of the source, before drinking it.

Metronidazole is used in different dosages to treat different illnesses. You’ll find detailed information in our book “The Survival Medicine Handbook” and in other standard medical references such as the Physician’s Desk Reference. You’ll also find this information at or

Here are the dosages and frequency of administration for several common indications:

• Amoebic dysentery: 750 mg orally 3 times daily for 5-10 days. For children, give 35 to 50 mg/kg/day orally in 3 divided doses for 10 days (no more than adult dosage, of course, regardless of weight).

• Anaerobic infections (various): 7.5 mg/kg orally every 6 hours not to exceed 4 grams daily.

• Clostridia infections: 250-500 mg orally 4 times daily or 500-750 orally 3 times daily.

• Giardia: 250 mg orally three times daily for 5 days. For children give 15 mg/kg/day orally in 3 divided doses (no more than adult dosage regardless of weight).

• Helicobacter pylori (ulcer disease): 500-750mg twice daily for several days in combination with other drugs like Prilosec (Omeprazole).

• Pelvic inflammatory disease (PID): 500 mg orally twice daily for 14 days in combination with other drugs, perhaps doxycycline or azithromycin.

• Bacterial Vaginosis: 500mg twice daily for 7 days.

• Vaginal Trichomoniasis: 2 g single dose (4 500mg tablets at once) or 1 g twice total.

All drugs have the potential for side effects, also known as adverse reactions. These are different from allergies, where your body actually mounts an immune response to a drug, such as in a penicillin allergy.

One particular side effect has to do with alcohol: drinking alcohol while on Metronidazole will very likely make you vomit.


Metronidazole should not be used in pregnancy. but can be used in those allergic to Penicillin.

Having antibiotics will give you an additional tool in the medical woodshed that just might, one day, save a life. They’re not toys, however, and should only be used when absolutely necessary.


Joe Alton, MD

joe bleachLearn more about antibiotics and their use in survival settings in our book “The Survival Medicine Handbook“, with over 250 5-star reviews on Amazon.

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