Yes, what bob said is true. You need to reduce the number items dropped by the monsters to prevent such things from happening.
The other option that is you is to turn on *DISABLE_THROWITEM . If I recall correctly, it works by that whenever you drop an item from your inventory, it vanishes rather than appearing on the floor. So the one issue with that is, you have to be careful on deciding whether you want or do not want an item since once you drop it, it will vanish forever ^^. Test it out and see if that is what you are looking for.