Pickle juice is made up primarily of salt and vinegar. Neither of these two things are healthy in large quantities and neither can we live without them. Salt is essential to our systems to maintain proper hydration levels, and while vinegar may not be itself important to us, acid in general is necessary to digest food, and it is said that a small amount of vinegar a day is quite good for you. Too much salt can lead to dehydration and too much acid can cause burns in your stomach lining.
There is not nearly enough acid or salt in a jar of pickle juice to serious harm anyone. It may give you a stomach ache, it may even cause people to vomit, but one jar will not kill anyone. Now if you drank a bottle a day that may cause damage to an organ or two after some years, but if you're drinking a bottle of pickle juice a day for ten years you probably have bigger problems.
I would say over all that technically drinking a jar of pickle juice is unhealthy.
