Qualified borosilicate glass is generally not harmful to the human body, poor quality borosilicate glass may precipitate lead when heated, causing harm to the human body. Borosilicate glass is a kind of high temperature resistance, low expansion rate, high light transmission, chemical stability of special glass, often used to make glass, so the regular borosilicate glass whether usual drinking or heating, will not contain chemicals, so the human body is generally not harmful, do not have to worry about drinking into the chemical substances. However, if the borosilicate glass is of poor quality, lead will be precipitated in the hot environment, and lead, as a toxic substance, will greatly damage human health. Excessive intake of lead by the human body may cause damage to the function of its own nerve cells, etc., leading to a grayish face and premature aging. It may even cause dementia. So for the sake of health, it is recommended to choose high borosilicate glass products produced by regular manufacturers.