People who are taking some western drugs should not eat vinegar because acetic acid can change the pH of the local environment in human body, so that some drugs can not work, sulfa drugs in the acidic environment is easy to form crystals in the kidney and damage the renal tubules, so when taking such drugs should not eat vinegar. When taking alkaline drugs such as sodium bicarbonate, magnesium oxide, gastric sopping, etc., vinegar should not be eaten, because acetic acid can neutralize alkaline drugs and make them ineffective. Vinegar is not suitable for taking antimicrobial drugs such as gentamicin, kanamycin, streptomycin and erythromycin, because the effect of these antimicrobials will be reduced in an acidic environment, which will affect the efficacy of the drug. Vinegar is astringent in nature. According to traditional Chinese medicine, acid is astringent, so when combining Chinese herbal medicines such as compound silver forsythia tablets with it, vinegar will promote the contraction of human sweat pores and destroy the active ingredients such as alkaloids in Chinese medicines, thus interfering with the sweating effect of Chinese medicines. When the Chinese herbal medicine such as compound silver forsythia tablets is combined with vinegar, vinegar will promote the contraction of the body’s sweat pores and destroy the active ingredients in the herbal medicine such as alkaloids, thus interfering with the sweating and relieving effect of the herbal medicine. It is not suitable for patients with gastric ulcer and excessive stomach acid because vinegar not only corrodes the gastrointestinal mucosa and aggravates the development of ulcer disease, but also has rich organic acid, which can make the digestive organs secrete a lot of digestive juices and thus increase the digestive effect of stomach acid, so as to avoid the increase of stomach acid and the aggravation of ulcer. Those who are allergic to vinegar and low blood pressure should not use it because vinegar can lead to rash, itching, edema, asthma and other symptoms in the body. In addition, some people who have discomfort to vinegar should be cautious to consume it. Patients who suffer from low blood pressure will have adverse reactions such as headache and dizziness and general weakness due to the lowering of blood pressure by consuming vinegar. Elderly people should avoid eating vinegar during the treatment and rehabilitation of fracture because vinegar can soften bones and decalcify, disrupt the dynamic balance of calcium elements in human body, which will promote and aggravate osteoporosis, make the injured limbs sore and tender, increase pain, and delay the healing of fracture.