How do you get rid of fleas on a puppy less than 12 weeks old?

To get rid of fleas on a puppy under 12 weeks, give the puppy a flea bath with a flea shampoo approved for use on puppies, use a flea comb, wash its bedding and treat the other adult animals in the home for fleas. It is potentially dangerous for puppies that are less than 6 weeks old to get fleas and if a puppy of this age gets fleas, they must be treated immediately.

Make sure to have everything necessary on hand so to keep from having the puppy escape during the bath.

1. The flea bath
A puppy under 12 weeks can safely take a flea bath, which can help to eliminate the fleas. Submerging fleas under water will kill them, although eggs on the puppy will remain and can still hatch. Use a gentle dishwashing liquid as a shampoo and make sure that the little puppy is completely wet. Massage the liquid around the puppy's legs, stomach, back and neck. Be sure to avoid the eyes and the inside of the ears.
2. The flea comb
A flea comb is useful for puppies of all ages and works best when the dog's fur is slightly damp; however, they can be used on a daily or even hourly basis with dry fur. 
3. Wash bedding
A puppy will have areas around the home where it likes to sleep and will often have a crate with bedding. Wash all of this bedding in hot water.
4. Treat the other adult animals
If there are other adult animals in the home, be sure to treat them with a flea protection medication. Fleas spread easily between pets and the adults can either get fleas or pass on fleas to the puppy once again.