Dogs sometimes eat things that are not food. Pica is defined as the persistent chewing and consumption of non-nutritional substances that provide no physical benefit to the animal. It can be a sign of distress or anxiety. There are many potential causes of this anxiety including changes in the social or physical environment or because of an internal oddness in how the animal perceives or interacts with the world.

Eating objects, such as rocks, can also be very dangerous for your dog, as these can be stuck in the stomach or intestine. Sharp objects, such as sticks, can cause damage to the delicate lining of the intestinal tract. It is therefore important that you know more about this behaviour to understand how to manage it appropriately.

Pica is the term used to describe the behaviour of eating things that have no nutritional value and provide no physical benefit to the animal, like plastic, rocks, or fabrics.

Eating of grass is very common in dogs and other animals (such as wolves or foxes) and is considered normal if non-harmful. It is thought that eating grass provides some physical benefit for dogs, for example to help eliminate worms.

Dogs have pica if they focus on, and seek out, non-nutritive substances for oral manipulation or consumption due to interactions between the dog’s genetic response and the social/physical environment out of context. This pica may then become an obsessive compulsive disorder.

It is possible for some medical problems to cause pica so it is important that all dogs with this behaviour are examined by a vet. Eating grass can be considered a relatively normal behaviour in dogs unless your dog is sick before or after doing it or the behaviour is very frequent or changes suddenly (i.e. your dog does it more often than usual). If you are concerned about any behaviour shown by your pet always consult your vet for advice. Dogs that lick surfaces may have some gastrointestinal upset and if this can be resolved the licking will stop.

If there is no medical condition causing the pica, it may be that your dog is using pica to to cope with situations where they feel uncomfortable, or when they feel very excited. When your dog does not know what to do, he or she may try to chew and eat things to relax. In this case you must help your dog to feel more comfortable with these situations. It is important to solve this problem as soon as possible, as the behaviour will become more established with time and repetition.

In some cases, pica is not caused by disease or stress. Dogs need to be mentally and physically stimulated, and exploring (especially with their mouth) is a normal behaviour for them, especially when young. If they do not find appropriate targets for this need, they may direct it onto less appropriate objects. Therefore it is important to exercise your pet enough, and provide it with a range of interesting toys and chews.

Toys that can be stuffed with food can be particularly useful, as they will keep your dog occupied for a long time redirecting the behaviour onto a more appropriate one. However, it is important that pets are supervised to prevent them from destroying the toy and swallowing pieces.

Your vet will discuss in detail potential causes of pica in your dog and may suggest referral to a behavioural specialist for further treatment.

It is always important to try to address the underlying cause of pica. In addition, you will want to stop the unwanted behaviour, and substitute it with something more appropriate. Pica can be prevented by making it physically impossible for your pet to eat inappropriate objects. You can hide all the items that your dog may try to eat or train your pet to be happy to wear a muzzle, and then muzzle them when at risk. You can also make the favoured substance less appealing, by mixing it with harmless but aversive chemicals.

If you catch your dog in the act of pica you need to interrupt him or her. Directly punishing your pet is very often unsuccessful, as in many cases dogs simply learn to perform the behaviour out of your sight, and sensitive or anxious dogs may be more stressed by repeated punishments.

Whatever is the cause of the behaviour, you should be aware that your attention (e.g. calling your pet or asking him/her to stop) is potentially a huge reward for your pet. If you see your pet showing unwanted behaviour of any kind they will often be distracted if you move away from them and engage in some interesting activity without obviously communicating with your pet (e.g. moving a food container, or playing with a ball). This way, you might be able to engage your dog’s attention and get them to choose to leave the inappropriate item to join you, without you drawing attention to the inappropriate action.

When your dog has left the object that was being eaten, you can leave your pet with some food scattered on the floor, or a chew or another food toy, and remove the inappropriate object while your pet is distracted. Food toys or chews are also appropriate objects that you can offer to your dog in these situations (before the dog starts eating something else) and at any time that your pet needs to chew, eat, and explore using its mouth. This can teach your pet a safe and appropriate alternative to pica.

In some cases, your veterinary surgeon may also suggest trying some medication to aid progress by reducing the signs displayed by your dog.

Finally, remember that the chances of resolving this problem are better with early intervention. The more time dogs spend eating inedible items, the more they learn to do it and so the more established becomes the behaviour.

If you are worried about any aspect of your dog’s behaviour seek help from your veterinary practice. If your vet is concerned they may wish to refer you to a specialist animal behaviourist.