Pica is a term used for having an appetite for things that have no nutritional value, for example paper, stones, wood, clothes, pebbles, cables etc.  Some  of these items can be harmful, toxic and or cause obstructions, constipation or damage to the intestines. 

Certain breeds are more prone than others, but puppies of all breeds tend to experience  pica.  There could be medical reasons and deficiencies  in diet for pica , but generally it is a behavioural issue.

If you experience this with your puppy or dog the first route is to distract them.  Lack of exercise, boredom, stress or anxiety may be contributing reasons.  Please check with your vet to ensure there isn't a medical reason, but a bored Wolfhound who feels they aren't getting enough attention, enough toys or fun things to do, will devise a million and one ways of ensuring they do and pica is one of them. 

PS.  Dogs do eat grass and it is not necessarily a sign  that they are poorly, and they won't always sick it up, the undigested grass does pass through and can be seen in the poo!