A Cup of tea (nettle) is a drink that restores 3 Hitpoints and 5% run energy, provided you have missing hitpoints. It can be obtained by using nettle tea on an empty cup.
A bucket of milk may also be added to the tea to create Cup of tea (milky nettle) which has the same effects and is used during the Ghosts Ahoy quest.
This particular kind of tea cannot be added to a tea flask. Nettle tea can be used in place of a regular cup of tea for the Panning guide during The Dig Site quest.