Apple cider vinegar (ACV) is a type of vinegar that’s made by fermenting apples with yeast and bacteria. It’s main active compound is acetic acid, which gives ACV its sour taste.

While ACV has many culinary uses, it’s becoming a popular home remedy for everything from acid reflux to warts. Some even claim that ACV treats cancer.

Keep reading to learn more about the research behind using ACV to treat cancer and whether this home remedy really works.

In the early 1900s, Nobel Prize winner Otto Warburg suggested that cancer was caused by a high level of acidity and low oxygen in the body. He observed that cancer cells produced an acid called lactic acid as they grew.

Based on this finding, some people concluded that making blood less acidic helped to kill cancer cells.

ACV became a method for reducing acidity in the body based on a belief that it’s alkalizing in the body. “Alkalizing” means that it reduces acidity, which separates ACV from other vinegars (such as balsamic vinegar) that increase acidity.

Acidity is measured using something called the pH scale, which ranges from 0 to 14. The lower the pH, the more acidic something is, while a higher pH indicates that something is more alkaline.

Most of the research surrounding ACV as a cancer treatment involves animal studies or tissue samples rather than living humans. However, a few of these studies have found that cancer cells grow more aggressively in an acidic environment.

One study involved a test tube containing stomach cancer cells from rats and humans. The study found that acetic acid (the main active ingredient in ACV) effectively killed the cancer cells. The authors suggest that there may be potential here for treating certain gastric cancers.

They add that, in combination with chemotherapy treatment, special methods could be used to deliver acetic acid directly to a tumor. However, the researchers were applying acetic acid to cancer cells in a laboratory not in a living human. Further research is needed to investigate this possibility.

Also important: This study did not investigate whether consuming ACV is related to cancer risk or prevention.

There is some evidence that consuming vinegar (not ACV) might offer protective benefits against cancer. For example, observational studies in humans found a link between vinegar consumption and a lower risk of esophageal cancer in people from China. However, consuming vinegar also seemed to increase the risk of bladder cancer in people from Serbia.

Above all, the concept that increasing the pH of blood kills cancer cells isn’t as simple as it sounds.

While it’s true that cancer cells produce lactic acid as they grow, this doesn’t increase acidity throughout the body. Blood requires a pH between 7.35 and 7.45, which is just slightly alkaline. Having a blood pH even slightly outside of this range can severely affect many of your organs.

As a result, your body has its own system for maintaining a specific blood pH. This makes it very hard to affect the pH level in your blood through your diet. Still, some experts have looked at the effects of an alkaline diet on the body:

  • One systematic review found that there was no actual research to support the use of an alkaline diet to treat cancer.
  • One human study looked at the link between urine pH and bladder cancer. The results suggest there’s no link between the acidity of someone’s urine and their bladder cancer risk.

Although, as mentioned, a few studies found that cancer cells grow more aggressively in an acidic environment, there’s no evidence that cancer cells don’t grow in an alkaline environment. So, even if you could change the pH of your blood, it wouldn’t necessarily prevent cancer cells from growing.

One of the biggest dangers of using ACV for treating cancer is the risk that the person taking it will stop following the cancer treatment recommended by their doctor while using ACV. During this time, cancer cells can spread further, which would make the cancer much harder to treat.

In addition, ACV is acidic, so consuming it undiluted can cause:

  • tooth decay (due to erosion of tooth enamel)
  • burns to the throat
  • skin burns (if applied to the skin)

Other potential side effects of consuming ACV include:

  • delayed emptying of the stomach (which can worsen the symptoms of gastroparesis)
  • indigestion
  • nausea
  • dangerously low blood sugar in people with diabetes
  • interactions with certain drugs (including insulin, digoxin, and certain diuretics)
  • allergic reaction

If you want to try drinking ACV for any reason, make sure you dilute it in water first. You can start with a small amount and then work your way up to a maximum of 2 tablespoons per day, diluted in a tall glass of water.

Consuming any more than this can lead to health problems. For example, consuming too much ACV likely caused a 28-year-old woman to develop dangerously low potassium levels and osteoporosis.

Learn more about the side effects of too much ACV.

The reasoning behind using ACV as a cancer treatment is based on a theory that making your blood alkaline prevents cancer cells from growing.

However, the human body has its own mechanism for maintaining a very specific pH, so it’s very hard to create a more alkaline environment through diet. Even if you could, there’s no evidence that cancer cells can’t grow in alkaline settings.

If you’re being treated for cancer and having a lot of side effects from the treatment, talk to your doctor. They may be able to adjust your dosage or offer some tips on how to manage your symptoms.