Onion tea has been used as a folk treatment for the common cold, flu and cough. Onions contain nutrients that help fight the cold, and herbal teas provide relaxation during recovery. Although there is no cure for colds, the study does not show the beneficial effects of onion tea, but the substances contained in the onions may enhance your immune system. If you are concerned about a cold or cough, consult a doctor for medical advice.

Immune Enhancement
Onion from the University of Northern Ireland, Belfast, contains researchers Peelin, which increases overall antioxidant activity in the blood, was published in the February 1999 issue of the European Journal of Clinical Nutrition. Antioxidants protect you from free radicals that cause cell damage and disease. Onions are also rich in vitamin C. Although vitamin C does not prevent colds, according to MayoClinic.com, vitamins may shorten the duration of symptoms in the event of a cold. Consumption of fruits and vegetables, including onions, helps to boost the body's immune response.
Herbal Remedies
When you have a cold, you should avoid alcohol, which can weaken your immune system and caffeine. According to Princeton Health Services, this may increase congestion. And dehydration. Some people choose to drink warm tea, but caffeinated tea may worsen the symptoms. Herbal teas, such as onion tea, do not contain caffeine and can even help you feel better. Vitamin C content and antioxidant effects in onion juice can increase the protection of the common cold.
Tea Food
Making onion tea can be as simple as cutting onions, boiled and drinking juice to quickly treat colds. You can add herbal tea ingredients to get a better taste. EnjoyingTea.com recommends ginger and onion tea for colds. Wash and cut five slices of ginger and two pieces of shallots. Put ginger, onion, a pinch of salt and 2 teaspoons of green tea into the teapot. Pour boiling water into the pot and let the tea soak for three to four minutes.
Dietary advice
Onions are a good balance part of the ced diet should include plenty of fruits, vegetables and grains to help boost your immune system when you have a cold or a cold. The Princeton Health Service recommends that you drink at least 8 ounces of clear liquid every two hours, plus onion tea to relieve your throat and relieve nasal congestion.