Flambeed is weak to any Water spell, including ice spells. Stunning him, putting a distance between you and him, then casting your strongest Water or Ice spell and repeating this process is a quick and easy way to take care of this monster, and is highly recommended. He uses melee and magic attacks, so players should bring food since prayer is not allowed. His melee attack is the more dangerous attack due to its accuracy, so it is advised to maintain distance from him as much as possible. Ice spells are especially useful for this purpose as they stun him. Ranging him is not recommended, as he has high ranged defence. It is not recommended to melee him either, as his melee attack is extremely accurate. Regardless of your approach, you will need to bring ice gloves to wield a weapon. Otherwise, when he attacks you, it will be unequipped, and you will be unable to fight him back except by punching him - you won't even be able to cast spells or use magic abilities.
Originally, Flambeed had a combat level of 149. This was changed to 199 with the release of the Dominion Tower. It was changed again to 128 with the release of the Evolution of Combat, and to 89 after the release of Legacy.
For a while after the release of the Evolution of Combat, there was a glitch that made Flambeed regularly hit for very high amounts of damage (often over 5000) with his melee attacks, regardless of whether Ice gloves were equipped. This made it difficult, if not outright impossible to fight him without stunning him and using ranged or magic. On the release of RuneScape 3 on 22 July2013, this was fixed by Jagex, and the cause was confirmed in the patch notes as a typo that accidentally gave him 10 times the melee strength Jagex intended him to have.