Do's and Don'ts

Keep your ferret up to date on his vaccines.
Keep his food and water bowl clean.
Keep him flea free!
Keep his ears clean, and his claws trimmed.
play with him often. Also watch him play when others are over (small children, other pets, etc.)
Check dishwashers and dryers and washing machines before loading. These are great places to hide!
Check bath water. A ferret's usual body temperature is 101.5. If it feels warmish to you, its chilly to them. Who wants a cold bath!?
Keep all medication, vitamins, supplements, etc. locked up and out of reach.
Check all the laundry before you wash it. Laundry is a great place for ferrets to hide.
Anything you don't want to be stolen, keep out of the ferret's reach. Keys, shoes, insoles, checkbook, phone; all of these are great things to stash.
Remember where your ferrets favorite stashes are and make note.
React quickly if your ferret appears to be sick or in trouble.
Check your dryer hoses for holes or breaks. Ferrets can uses these to escape to the outside.

Keep lose cords laying around. Bundle them up out of the way
Have recliners where a ferret can access them. The mechanics of one can kill a ferret.
Leave candles burning unattended. Ferrets have no fear or common sense when it comes to fire. They could and will check it out, burn themselves and knock the candle over in the process.
Avoid latex toys. These will break apart and the pieces can get into a ferrets digestive track and kill your ferret.
Leave fireplace doors open.
Blame the ferret if he bites you during rough play.
Expose to temperatures above 80 degrees Fahrenheit
Chocolate or sweets
Smoke around your ferret
Step on your ferret
Step on a lumpy rug or piece of clothing
Drop your ferret
Use clumping cat litter (the litter get stuck in their noses)
Change diet suddenly
NO TINSEL on your Christmas Tree
No Mouse poison or open mouse traps (These work on ferrets too)
Don't leave household chemicals accessible to your ferrets.