How do I stop my 9 week old puppy eating its own poo?

I have heard that putting a bit of meat tenderizer in his food willmake the poo un appitizing for him.
Also it's a good habit to pick feces up straight away to avoide further contamination. This helps prevent the spread of worms, and the parvo virus. I know sometimes it's hard to get it right away, but the meat tenderizer should do the trick! :)

How long have you had the pup and where did you get him/her from? It could be something that she/she learned to do (or didn't learn not to) from her previous 'home'. It could be diet related.

Talk to your vet about it and make sure that the pup is healthy.

From what I have heard, making sure that she/he has good quality food appropriate for her/his age and size, is one step.

The next step is to add something to the food that makes the feces less appealing. Another 'additive' that I have seen used (check with your vet before adding anything to the pup's food) is crushed pineapple.

Here is a pretty good article on WHY dogs eat poop.
20 Reasons Why Dogs Eat Poop (Coprophagia, Pica)