Can drug sniffing dogs detect previous drug use?

Question

I am asking this again, in order to get more answers.

Instead of doing random drug testing, my high school hired a private company to patrol campus with drug sniffing dogs in order to stop students from dealing on campus.

My dean told our class the dogs can actually detect if a student used drugs s few days prior (including alcohol).

Is this possible? I think he is just lying in order to scare us.

I always though a shower, change of clothes, and freshly brushed teeth could eliminate the scent of drugs from your body.

Answer 1

No The Dog Can't smell them on you if you shower brush teeth and wash your clothes only if you are in possion or you have been useing them that day in the same clothes or others around you your teacher only want to scare you !!!  

Answer 2

It depends on the dog's training, and it depends on the drug.  Meth users reek of the drug and have a very specific smell so those who "geek" will surely be found out by dogs.  Other than Meth, I'm not aware of drug smells the dogs will target.

Answer 3

He is just trying to scare you. Keep in mind the dogs can smell residue on clothing, backpacks, books, anything you can leave a faint odor. These dogs are trained to look where people hide stuff.