Dembele, 22, went under the knife in Finland after injuring himself in training last week. He will miss the rest of the season as his injury nightmare at Camp Nou continues.
"The first-team player Ousmane Dembéle has successfully undergone surgery in Turku, Finland where he was operated on by Dr. Lasse Lempainen for a ruptured tendon in his proximal hamstring in his right thigh." the Catalan club said in a statement. "The Frenchman will be out for around six months.
"The striker was continuing his recovery from the hamstring injury when he was forced to retire from a training session at the Ciutat Esportiva last week. Subsequent tests confirmed a complete rupture to the tendon in the proximal hamstring of his right leg."
Barça hope the Spanish FA will grant them permission to make an emergency signing to provide depth in attack between now and the summer.