Plants
Peppermint and spearmint both come from the Lamiaceae plant family. Peppermint is called Mentha canadensis and spearmint is Mentha spicata. Peppermint was actually created through a combination of spearmint and water mint. Both types of mint contain menthol, which accounts for their similar benefits.

Uses
Peppermint and spearmint have similar health benefits; although peppermint seems to be more effective, spearmint is more gentle. Both spearmint and peppermint are used to boost your mood, mental clarity and alertness, as well as boost metabolism, fight insects and help you breathe better. They seem to help gas, encourage digestion and appetite, alleviate nausea and ease cramps and diarrhea. Both oils can alleviate pain and ease symptoms of colds.

Applications
Spearmint and peppermint oils are two of the few essential oils that can be ingested. This method is mainly used for digestive concerns. Choose one type of oil and put one drop in one cup of warm water with a small amount of honey. Mix this and drink it. Peppermint oil also comes in enteric-coated capsules. For uses other than digestive concerns, put one to two drops spearmint or peppermint oil in a diffuser or smell it straight from the bottle.

Warnings
Peppermint is a strong oil you should use in moderation. It can cause irritation to the skin and the mucous membranes and can cause heartburn. Avoid this oil when you are pregnant or breastfeeding, and do not give it to a baby or small child. Avoid ingesting peppermint if you have gallstones, GERD, a hiatal hernia or are taking stomach acid-reducing medications, medications for blood pressure or diabetes, or cyclosporine. Spearmint is weaker than peppermint and generally seen as safer, but it can cause allergic reactions. Also, if used in high doses, it can cause skin rashes and heartburn.