Peppermint in itself is a mixed or hybrid mint. It is a cross between watermint and spearmint. Peppermint tea, or mint tea is a herbal tea. It is made by infusing or diffusing peppermint leaves in hot water. Hot water to speed up the diffusion process. Water in itself to catch all the extracted material from the plant. As with any infusion you could simply let the leaves sit in cold water. But this would takes weeks to months, so for the purpose of time it is typically hot water infusion.
The good therapeutic benefits to mint tea is that the leaf has a lot of essential oils. Between the smell and the ingestion it could have many therapeutic effects. The main health effect comes from the menthol essential oil in the plant. Menthol is essentially what we know real mint to be called. More importantly during cold and flu season menthol will help to expand lung passageways. This allows for more air to enter. If you have a cold this is something that will make the cold more bearable.
Furthermore, you can see some type of menthol in most cold medication and a lot of chewing gum and mouthwash. They all have the same refreshing and lung opening effect of expanding lung passageways. This is also something that is useful if you are trying to detox the lungs. Menthol also helps with the digestive system as well as the excretion of gastric juices. Menthol also acts as an anti-inflammatory which can help in both the stomach and the intestines.