Garlic - also known as "Wonder Drug", helps fight many immunity and fatigue problems. If 2 raw pieces of garlic are eaten early in the morning before breakfast with water, it really helps to boost immunity.
Raw Onions are very good for your heart. So, once a day is very good.
Spices like Turmeric and black pepper are well known to cure many diseases. Hot milk with turmeric powder is known to cure many disorders and help boost immunity.