Apple cider vinegar, or cider vinegar, is a vinegar made from cider, and used in salad dressings, marinades, vinaigrettes, food preservatives, and chutneys. It is made by crushing apples, then squeezing out the juice. The apple juice is then fermented by yeast which converts the sugars in the juice to ethanol. In a second fermentation step, the ethanol is converted into acetic acid by acetic acid-forming bacteria (Acetobacter species), yielding cider vinegar. The acetic acid, together with the malic acid naturally present in apple juice, contribute to the sour taste of this vinegar.

Apple cider vinegar (ACV) is one of the three most common vinegars and is made from fermented apples. This acidic solution is used around the world as a food flavoring and preservative. ACV contains a variety of flavonoids, such as gallic acid, catechins, caffeic acid, and ferulic acid. Animal studies have reported that ACV has a variety of pharmacological functions, including antioxidant, anti-inflammatory, antidiabetic, antihypertensive, and antihyperlipidemic properties.