Apple cider vinegar is a favorite remedy among natural health enthusiasts and is often used to treat a wide variety of medical and cosmetic ailments, despite the lack of scientific data on the subject. Anecdotal evidence is usually used to prove the effectiveness of apple cider vinegar, but it can also reveal its downsides. Reports of bad side effects from the use of apple cider vinegar are common, although they often go unrecognized by supporters.


For thousands of years, humans have used vinegar as a folk remedy for any number of problems. The Greeks and Babylonians used vinegar for medicinal purposes, and apple cider vinegar itself was used to treat wounds in the Civil War and World War I. Today's use of apple cider vinegar as medicine stems from the rising popularity of "common sense" treatments in the 1950s, when Dr. D.C. Jarvis published a book extolling its virtues. This has led to use of the product in place of medical treatment, overuse and a general ignorance of its possible harmful side effects.


Claims made about apple cider vinegar's healing potential include the prevention of muscle fatigue, stamina and metabolism increases, improved digestion, clear skin and allergy relief. Along with these minor claims, enthusiasts and sellers also advertise that apple cider vinegar reduces cholesterol levels, prevents bladder stones and urinary tract infections, strengthens the immune system, cures obesity and arthritis, and lowers heart disease risks. Whether or not this remedy has worked for some people, no studies have been done and the FDA has had to crack down on sellers for making unsupportable claims and potentially exposing consumers to other health risks associated with the vinegar.


Like its positives, much of the negative side of apple cider vinegar also comes from anecdotal and case reports. Although some people seem to be able to use apple cider vinegar over the long term with no ill effects, others have experienced a variety of downsides with both short-term and long-term use. Common side effects are the destruction of tooth enamel over time, heartburn and nausea. Testing has proven the existence of high levels of yeast in some products, coinciding with complaints made by women who developed yeast infections and thrush from using apple cider vinegar.


People with digestive problems and food allergies have also experienced negative side effects from the use of apple cider vinegar. The vinegar is commonly suggested to heartburn sufferers as a way to restore the balance of acid in the stomach; however, given the variety of heartburn causes, apple cider vinegar can just as easily make the situation worse. Complaints have included stomach and throat pain, increased heartburn and acid reflux vomiting. One case study involved a patient who had suffered esophageal burn from apple cider vinegar tablets. Other users have had allergic reactions to the product in the form of hives, rash, itching and difficulty breathing.


Drug interaction is also a concern for those taking apple cider vinegar. Due to the product causing low potassium in the blood, people taking digoxin should avoid it without first checking with their doctors. Other potentially harmful combinations include the use of drugs like bumetanide, chlorothiazide, chlorthakidone, ethracrynic acid, furosemide, hydrochlorothiazide, metolazine, spironolactone-HCTZ, torsemide and triamterene/HCTZ with apple cider vinegar. Those with any other major health concerns should also consult a doctor before using apple cider vinegar. Whether apple cider vinegar's health benefits are real or not, the range of experienced side effects shows that it should be used cautiously.