Contains No Added Ingredients 100% Pure Menthols. Add a few crystals to a small bowl of hot (not boiling) water. A powerful vapour is produced. An alternative method to unblock a stuffy, congested nose is by using menthol. Menthol is an organic plant extract, sourced from the peppermint plant and various other mint plants. The oil is extracted from the leaves through the process of distillation, but is also commonly produced synthetically. Therefore it is important to buy from a trusted source. Premium Grade Quality Menthol Crystals.