Kale

Kale is a green foliage vegetable that has potent immune-boosting properties. Kale is a powerful alkalizer and liver and blood cleanser. It strengthens the immune system and helps the body eliminate pollutants, while its anti-inflammatory properties increase inflammation in the body.
According to nutritionists, kale is a very nutritious vegetable; consuming kale juice aids digestion and provides the nutrients a person with a fever needs to gain energy.