High concentrations of acetic acid are harmful and low concentrations of acetic acid are harmless. 1 High concentration of acetic acid: High concentration of acetic acid can attack the respiratory system, causing nasal bleeding, coughing, and can even induce chronic pharyngitis. It can also cause redness, swelling, rash and blisters on the skin and mucous membranes. Prolonged exposure to acetic acid can cause dryness of the eyes and conjunctival congestion, etc., and direct contact should be avoided to avoid damage to the body in life. 2. Low concentration of acetic acid: generally is a diluted acetic acid solution, generally does not cause harm, such as common vinegar in daily life, a small amount of consumption of beneficial to the body, can promote the metabolism of sugar, reduce cholesterol, if consumed too much can lead to indigestion, diarrhea, etc., according to their own situation to choose. Pure acetic acid is harmful to the human body, life need to pay attention to, avoid contact.