I bought some, having heard about it. Only took it once. In pill form, it can get stuck in the throat and cause horrible damage. And like another user said, it can strip enamel, and cause the stomac to have problems as well. It is an acid, and taking it straight is risky.
"Undiluted apple cider vinegar, in liquid or pill form, may damage the esophagus and other parts of the digestive tract. Apple cider vinegar drinks may damage tooth enamel if sipped."
"Excessive doses of apple cider vinegar have been found to cause damage to the stomach, duodenum, and liver in animals."
"One case report linked excessive apple cider vinegar consumption with low blood potassium levels (hypokalemia) and low bone mineral density. People with osteoporosis, low potassium levels, and those taking potassium-lowering medications should use caution."
Link provides this info, and more, including the possible benefits: