Fun Facts: Botanical name:Mentha piperita or Balsamea Willd. It is a cross between spearmint and watermint
Uses: (Disclaimer) Indigestion, nausea, digestive headaches, gas, bloating, cramps, irritated bowel
Caution: Be careful when using menthol oils and some people are dangerously allergic. People with gastroesophageal reflux disease, or GERD, should not use peppermint oil.
Personal Experience: The difference between mint and peppermint is crucial to me because my son is highly allergic to ingestion of menthol and mint products. However, he is not at all allergic to peppermint. He uses peppermint toothpaste, eats peppermint candy, chews peppermint gum and other peppermint products with no reaction. When he was 3 years old, his father gave him a mint chocolate and he broke out in hives and went to the emergency room. I gave him a cough drop for his coughs around age 4, and he broke out in hives again, screaming that he couldn't breath. After another rush to the emergency room and several doses of Benedryl, he was diagnosed with a mint allergy and prescribed an Epi Pen. In fact, I had to use that scary Epi Pen when he was around 5. A well intention friend gave him mint chocolate chip ice cream without my realizing it. Ever since then, my son has been very careful about asking about anything new has mint in it. Peppermint is a cross between spearmint and watermint while mint refers to any variety of mint. I still do not have a clear cut answer on why my son is allergic to mint/spearmint, but not peppermint.
I mostly use peppermint in form of tea. I keep a can of Heather's Tummy Teas Organic Peppermint around the house to reduce gas and bloating during menstrual cycle. It's also pretty effective with indigestion, nausea and headaches resulting from greasy/rich restaurant food. My favorite is the Organic Peppermint from Tealeaves.com. It's individually packed bags keep the herb fresh and tea bags themselves are fancy luxury hotel style. It's a bit pricey for peppermint tea though. You can find a variety of this tea in most grocery stores (HEB, Walmart, Target, etc). Last week, my husband complained about a headache, nausea and indigestion from the sweet and sour shrimp he had after church. I gave him a very tall glass of peppermint tea and a probiotic yogurt drink. He recovered after about 2 hours. Our friend, who had the same symptoms from the same food (we call the restaurant the next day) and she had to take a day off.
Menthol is the active oil in peppermint. In fact, it was first isolated in peppermint. Product with menthol are endless, ranging from mouth wash, cough drops, vapor rubs, and even soap. Growing up, our family's go-to med for cold and cough was the Chinese White Flower Oil. You can find most Chinese meds online these days, especially on Amazon.
NIH has a great database on menthol.