An inhaler is a device used by asthma sufferers to help them breathe more easily. It is a handheld device that delivers medication directly into the lungs, allowing the user to take in the medication quickly and effectively. Inhalers come in various forms, including metered-dose inhalers, dry powder inhalers, and nebulizers. They are typically prescribed by a doctor and can be used to treat both acute and chronic asthma symptoms.