Serializable Transactions are a type of database transaction that ensures complete isolation from other transactions. This means that when multiple transactions are executed simultaneously, each one appears to be the only transaction in the system. This prevents issues like dirty reads, non-repeatable reads, and phantom reads, ensuring data integrity. To achieve this level of isolation, database management systems often use locking mechanisms or timestamps. While serializable transactions provide the highest level of consistency, they can also lead to reduced performance due to increased waiting times for locks, making them less suitable for high-concurrency environments.