The Fire or Fire Up is a recurring item in the Bomberman series. It increases the player's max blast radius by 1. In grid-based Bomberman games, this means the player's bomb explosion will extend by one tile. In many free-area Bomberman games, this increases the spherical blast radius by a certain amount.
Although it is meant as a "good" item, the Fire item can be more of a detriment than a blessing to some players who may find themselves dying in their own blasts. Typically, players should be wary of the size of their blast. When you collect more Fire items, you should be more cautious about being lined up with your own bombs. It may be a good idea for some players to keep out of reach of your bombs for the first few you set upon gaining another Fire item when your count surpasses around 4 (including the two you are usually given from the start), and taking the opportunity to notice the new size of your explosions so you can better judge them. Some players, though, may be better off to destroy excess Fire items rather than pick them up, if they are unable to cooperate with larger blasts.