Ladies, do you take any immune boosters when it is flu season? What are they?

I usually take Vitamin C supplements (like Redoxon) whenever I feel that I may be coming down with cold/flu. Not sure if it's psychological, but I find that it sometimes help in prevention. Also, if I'm already down with flu/cold, it seemed to aid in recovery. Perhaps it's placebo effect. But since it does no harm to my body and tastes good (I usually opt for the effervescence tablets), I have no qualms taking those. :)