Culinary uses

Vinegar is commonly used in food preparation, particularly in pickling processes, vinaigrettes, and other salad dressings. It is an ingredient in sauces such as mustard, ketchup, and mayonnaise. Vinegar is an essential component of chutneys. It is often used as a condiment.                                    

Condiment for fish and chips    

 Britons commonly use malt vinegar (or non-brewed condiment) on chips; it may be used in other territories where British-style fish and chips are served.                                          

Flavouring for potato chips - In the case of American-style chips or crisps, many manufacturers of pre-packaged potato chips/crisps feature a variety flavored with vinegar and salt.

Condiment for French Fries, particularly in the Northeastern United States

Vinegar pie - is a North American dessert made with a vinegar to one's taste.

Pickling - any vinegar can be used to pickle foods.

Cider vinegar and sauces - cider vinegar is not usually suitable for use in delicate sauces.
Substitute for lemon juice - cider vinegar can usually be substituted for lemon juice in recipes and obtain a pleasing effect.

Saucing roast lamb - pouring cider vinegar over the meat when roasting lamb, especially when combined with honey or when sliced onions have been added to the roasting pan, produces a tasty sauce.

Sweetened vinegar is used in the dish of Pork Knuckles and Ginger Stew which is made among Chinese people of Cantonese backgrounds to celebrate the arrival of a new child.

Sushi rice - Japanese use rice vinegar as an essential ingredient for sushi rice.

Red vinegar - Sometimes used in Chinese soups

Medicinal uses

Many remedies and treatments have been ascribed to vinegar over millennia in many different cultures. However, few have been verifiable using controlled medical trials and several that are effective to some extent have significant risks and side effects.

Cholesterol
A scientific study published in 2006 concluded that a test group of rats fed with acetic acid (the main component of vinegar) had "significantly lower values for serum total cholesterol and triacylglycerols", among other health benefits.

Blood glucose control and diabetic management
Small amounts of vinegar (approx. 20 mls or two tablespoons of domestic vinegar) added to food, or taken along with a meal, have been shown by a number of medical trials to reduce the glycemic index of carbohydrate food for people with and without diabetes. This has also been expressed as lower glycemic index ratings in the region of 30%.

Diet control
Multiple trials indicate that taking vinegar with food increases satiety (the feeling of fullness) and so reduces the amount of food consumed. Even a single application of vinegar can lead to reduced food intake for a whole day.

Treatment for jellyfish stings
Applying vinegar to jellyfish stings deactivates the nematocysts. However, placing the affected areas into hot-water is a more effective treatment because the venom is deactivated by heat. The latter requires immersion in 45 degrees celsius (113 F) water for at least four minutes for the pain to be reduced to less than that of vinegar.However, vinegar should not be applied to portuguese man o' war stings, since their venom is different and vinegar can actually cause the nematocysts from their venom to discharge, making the pain worse.The hot water immersion or cold ice pack treatments have been shown to be the best for treatment of portuguese man o' war stings.

Traditional and anecdotal treatments
-Hippocrates prescribed vinegar for many ailments, from skin rash to ear infection.
-Vinegar is a folk medicine used in China to prevent the spread of virus such as SARS (Severe Acute Respiratory Syndrome) and other pneumonia outbreaks:
-In February 2003, an outbreak in China's Guangdong province of an atypical pneumonia caused massive demand and soaring prices for vinegar, isatis root, and other medicines believed to to be useful in killing the infectious agent.
-The therapeutic use of vinegar is recorded in the second verse of the nursery rhyme Jack and Jill: Went to bed and bound his head / With vinegar and brown paper. As with some nursery rhymes, there is truth in the story. The vinegar used would likely have been cider vinegar.
-Apple cider vinegar is a much more useful astringent than ice and will reduce inflammation, bruising and swelling in approximately a third of the time that ice will take. Application is directly onto the skin with a flannel, and left on for an hour or so.
-Apple cider vinegar in particular is often touted as a medical aid, from cancer prevention to alleviation of joint pain to weight loss. Claims of its benefits go back at least to Hippocrates. In 1958, Dr. D. C. Jarvis made the remedy popular with a book that sold 500,000 copies.
-Claims that cider vinegar can be used as a beauty aid also persist, it is a powerful remedy for Acne skin conditions when diluted 50:50 with water and used as a toner,despite the fact that apple cider vinegar can sometimes be very dangerous to the eyes. The acid will burn and the eyes will become red, but no damage to the eyes has ever been described. If the vinegar contains mother of vinegar the slime bacteria of the mother can cause Ophthalmia neonatorum .
-Many believe that vinegar is also a cure to mild to moderate sunburn when soaked on the area with a towel or in a bath.
-Cider vinegar is also claimed to be a solution to dandruff, in that the acid in the vinegar kills the fungus Malassezia furfur (formerly known as Pityrosporum ovale) and restores the chemical balance of the skin.
-Cider vinegar is a natural remedy for yeast infections, when diluted with water and used as a douche.

Veterinary treatment

Vinegar along with hydrogen peroxide (H2O2) is used in the livestock industry to kill bacteria and viruses before refrigeration storage. A chemical mixture of peracetic acid is formed when acetic acid is mixed with hydrogen peroxide. It is being used in some Asian countries by aerosol sprays for control of pneumonia. A mixture of five-percent acetic acid and three-percent hydrogen peroxide is commonly used.

Apple cider vinegar can be used to prevent some problems in the digestive systems of dogs, such as E. Coli. The vinegar is acidic until it enters the dog's body, and it lines its intestines. E. coli cannot attach to an alkaline vinegar-coated intestine.

Cleaning uses

White vinegar is often used as a natural household cleaning agent. With most such purposes dilution with water is recommended for safety, reduced risk of damaging certain surfaces, and budgetary reasons. It is especially useful for cleaning mineral deposits on glass, inside a coffee maker, or other smooth surfaces. Care should be taken to not allow contact with eyes (if such contact occurs, the eyes should be flushed immediately and persistently with warm water) or skin (the affected skin area should be washed thoroughly after use).

Agricultural and horticultural uses

As a herbicide

Vinegar can be used as a herbicide as shown by scientific trials reported by the US Dept of Agriculture in 2002. Vinegar made from natural products classifies as organic and so there is interest in it being used on farms/orchards/gardens certified as organic. The trials showed that a number of common weeds could be effectively controlled using vinegar with 5% to 20% acetic acid. The lower concentration is less effective. A crop of corn can be sprayed with vinegar at 20% strength without causing harm to that crop and so it can be used to help keep a corn crop clear of weeds.

Acetic acid is not absorbed into root systems and so vinegar will kill top growth but perennial plants will reshoot.

Commercial vinegar available to consumers for household use does not exceed 5% and solutions above 10% need careful handling since they are corrosive and damaging to skin. Stronger solutions (i.e. greater than 5%) that are labeled for use as herbicides are available from some retailers.

Miscellaneous uses

-When a bottle of vinegar is opened, mother of vinegar may develop. It is considered harmless and can be removed by filtering.
-When vinegar is added to sodium bicarbonate (baking soda), it produces a volatile mixture of carbonic acid rapidly decomposing into water and carbon dioxide bubbles, making the reaction "fizz". It is exemplified as the typical acid-base reaction in school science experiments. The salt that is formed is sodium acetate.
-Vinegar is a very effective way to remove rust from metals.
-Vinegar neutralizes lye, a strong base.
-Some countries, Canada as an example, prohibit the selling of vinegar over a certain percentage acidity.
-According to the Prophet Muhammed, vinegar is one of the best condiments.
-Lord Byron would consume vast quantities of white vinegar in an attempt to keep his complexion pale.       
-Some people also believe that vinegar can be used as a detoxification agent for marijuana, but this is myth.
-Posca, a Roman legionaries' basic drink was vinegar mixed with water and optional honey.

Source:Wikipedia

See also: www.infozeek.net, www.d-i-wine.com