Consumption of excessive amounts of vinegar is unhealthy. It is a relatively strong acid, and can irritate the throat and stomach, damage tooth enamel, weaken bones, and strain the kidneys.
If taken, doctors recommend diluting vinegar with water to cut down the acid content. Vinegar has also been linked to dangerous drug interactions with medication like diuretics and insulin. Apple cider vinegar is used by some people to treat diabetes; while it may help regulate blood sugar levels, doctors warn against using it as a substitute for diabetes medication. It is also taken as a folk remedy to combat obesity; again, doctors warn against this in favor of a sensible diet and exercise.