It is the first aid shipment to enter that area since a Russian-backed humanitarian pause went into force seven days ago.
Up to 46 truckloads of aid entered the Douma district in Eastern Ghouta through the Wafidin crossing northeast of Damascus.
The long-awaited shipment entered a day after the UN announced it was sending the shipment.
Earlier in the day, the Russian Reconciliation Center in Syria said the rebels in Eastern Ghouta pledged to allow civilians to leave that area in exchange for the entry of aid.
Due to the escalation of military showdown in Eastern Ghouta, the UN and other humanitarian organizations sounded the alarm about the worsening situation in that area where 400,000 people live.
Eastern Ghouta has been the major threat to Damascus since the rebels took hold in that area in 2012, with armed militants launching attacks on the capital with mortar shells and in some instance through implementing incursion attempts.
Four major rebel groups are currently positioned inside Eastern Ghouta, namely the Islam Army, Failaq al-Rahman, Ahrar al-Sham and the Levant Liberation Committee, or the al-Qaida-linked Nusra Front.
Eastern Ghouta has grabbed international attention recently since the military showdown has started to gain momentum on Feb. 18.
The UN Security Council adopted Resolution 2401 on Feb. 24, which requires all parties in Syria to immediately cease clashes and provides a sustained humanitarian break for at least 30 days across Syria.
Two days later, the Russians demanded a daily humanitarian pause for five hours in Eastern Ghouta specifically.
But those initiatives have slightly reduced the number of rebels' mortar shells on the capital and the Syrian airstrikes and bombardment of Eastern Ghouta.
The situation becomes calm during the five-hour-long truce, but the military confrontation continues right afterward.
The Syrian Observatory for Human Rights said the government forces' bombardment and airstrikes on Eastern Ghouta have killed over 600 people since the situation started flaring last month.