Nausea
Studies have concluded that ginger root tea helps in treating nausea connected with pregnancy, motion sickness and chemotherapy.
Flu
Historically, ginger root tea has been prescribed to fight illness and infection for people of all ages. Ginger root tea acts as a sheild to the high levels of prostaglandins that induce fever, headaches, and cramps. This process aids the immune system in fighting the flu and other illnesses.
Source:
http://www.sciencedirect.com/science/article/pii/S0278691502000376
https://bmccomplementalternmed.biomedcentral.com/articles/10.1186/1472-6882-8-46
http://www.sciencedirect.com/science/article/pii/S0952327897905871
https://books.google.com/books?id=zfxLvxEvAh0C
http://www.sciencedirect.com/science/article/pii/S0952327802904412