You can drink it. There was a news column that provided a 12 hour and 24 hour comparison with the tea soup of the newly brewed Anhua black tea. Overnight use of Anhua black tea: Anti-cancer and anti-oxidation. After Anhua black tea is left overnight for a long time, the tea soup will gradually turn reddish brown. This phenomenon is due to the oxidation of tea polyphenols into reddish brown tea pigments.