No. Normally, oxygen is not required as our Annapurna Base Camp trek itinerary is designed in such a way so that it allows enough acclimatization. In addition, we provide Diamox, a medication that suppresses altitude sickness symptoms, from the beginning to prevent falling sick. However, in case of severe altitude sickness, we will descend to a lower altitude immediately, which is extremely rare in the Annapurna region trek.