OTRIVIN MINI NASAL DROPS opens and clears the nasal passages. It really works by narrowing down the blood vessels supplying the nasal passage. This allows swollen blood vessels of the nasal tract to return to its normal dimension which enables the air to pass through the nostrils a lot more freely.Polyp thanh qu?n là c?n b?nh ?nh h??ng ??n gi?ng n