Body lice are primarily treated by thoroughly washing yourself and any contaminated items with soap and hot water. Dry cleaning and ironing clothing that cannot be washed is also effective.
If these measures don't work, you can try using an over-the-counter lotion or shampoo — such as Nix or Rid. If that still doesn't work, your doctor can provide a prescription lotion. Lice-killing products can be toxic to humans, so follow the directions carefully.