Disagreeing with consul Gnaeus Mallius Maximus, Caepio's army faced a huge loss at the Battle of Arausio.
He was a successful Roman general as demonstrated by his triumph in 107 BCE for his efforts in Further Spain. The next year he was elected consul with Gaius Atilius Serranus.
On the way to aid the Romans as they fought in Germany, he recaptured the city of Tolosa in 105 BCE. The city had revolted against the Romans. There he and his soldiers found some 50,000 fifteen-pound bars of gold and 10,000 fifteen-pound bars of silver. The silver was shipped back to Rome, and the gold was lost in transit.
Though he was ordered to obey the consul, Gnaeus Mallius Maximus, he refused to listen because Mallius was a novus homo. When Mallius seemed about to reach a treaty, Caepio struck against the Germans. At the Battle of Arausio, some 80,000 soldiers and 40,000 servants and camp followers were killed. When he returned to Rome, Gaius Norbanus tried him for "loss of his army" since he had caused this defeat because of his rashness. He lost his citizenship, was forbidden fire and water within eight hundred miles of Rome, fined 15,000 talents of gold, and forbidden to see or speak to his friends or family until he had left for exile. After this sentence, he either died in prison and his body was placed on display, or he spent his life in exile in Smyrna in Asia Minor.