From RebirthRO Wiki
Tasty and sweet bubble gum.
- Item drop rate increases by 100% for 30 minutes.
- (Note: This does not make things at 50%, 100%. Bubblegum gives a second drop chance, should the first one not drop. So if your item is a 50% drop chance, it checks to see if it dropped during the first check. If it did not, it runs the check again at the same % chance.)