Teva Pharmaceutical Tuesday launched an unsolicited bid to buy Mylan for $31 billion in a transaction that would create a behemoth in generic drugs.

Teva's cash-and-stock bid would quash an unsolicited bid by Mylan earlier this month to acquire Perrigo for $28.9 billion. Teva said its bid amounted to superior value for Mylan shareholders compared with Mylan's approach to Perrigo.