fixing the 24-hour summer flu

benadryl 12.5 mg
gatorade ice
passionfruit drink: try TnT's market or a vietnamese grocer or convenience store.
ginger beer

the ginger beer is for the stomach
the passionfruit and benadryl is for sedation. the latter also slows down urination and tendency to vomit
the gatorade ice provides water for hydration and sugar for energy

if this does not work, the emergency umeboshi & sweet rice congee (okayu) cure consists of japanese rice cooked, one to 2 bowls depending on severity of flu with one umeboshi, once every two-three hours with chinese green tea.

you can get umeboshi at tnt's too or at the konbini on robson street.

proof that the emergency okayu exists: http://en.wikipedia.org/wiki/Rice_congee#Japanese