Although apple cider vinegar can have positive effects, for some people it is dangerous – endocrinologist Zukhra Pavlova warned about this.
The doctor reminded that apple cider vinegar (like any vinegar) contains a lot of acid. Therefore, taking it can be dangerous in cases where there are problems with the digestive tract.
“For people with problems with the digestive system and the gastrointestinal tract in general, this product can cause significant harm to health,” the physician told the portal “Doctor Peter”.
Pavlova also noted that apple cider vinegar should not be used in case of existing disorders in the functioning of such organs as the kidneys and liver.
The specialist added that drinking water in the morning should not be identified with lemon juice and water with apple cider vinegar. Such drinks may seem equally healthy due to the sour taste, but the lemon in the body acts like an alkali, not an acid. Thanks to this property, it helps to balance the acid-base balance – apple cider vinegar does not have this quality.
Apple cider vinegar helps lower blood sugar levels – studies
Pavlova emphasized that it should be used strictly in moderation, carefully.
Scientists have answered whether apple cider vinegar helps to lose weight
Earlier, the MedikForum.ru portal wrote that beer can be beneficial for intestinal microflora. 
Zukhra Pavlova Healthy lifestyle endocrinologist, Moscow State University M. V. Lomonosov, candidate of medical sciences