When I have the flu I prefer drinking either Chamomile or Peppermint Tea with a bit of honey to help soothe my throat.
The teas are both hydrating and provide antioxidants to your body to help flush out the flu virus and make you feel better.
The honey in the tea helps to soothe and lubricate your throat even if you don't have a sore throat.
Drinking some orange juice along with the tea can provide you with some Vitamin C which helps to boost your immune system as well.