Use olive leaf extract capsules (250 mg) three times per day with meals to treat the flu, colds, sinusitis, herpes, psoriasis and allergies.More tips for winter health:Eat plenty of oranges, grapefruit, strawberries, kiwi fruit and vegetables such as red and green peppers and broccoli for a daily dose of natural vitamin C.A cup of green tea with honey and lemon will do a lot to fight off common wi