How to do a Food Trial

Advice on conducting a food trial for your pet

You have been asked to do a food trial with your pet so we can see if they have a food allergy. Food allergies can cause many symptoms including:

  • Itchy skin and feet.
  • Ear infections.
  • Anal gland problems.
  • Inappetence.
  • Vomiting.
  • Diarrhoea.
  • Mucus or blood in faeces.
  • Flatulence.

During the food trial you must make sure your pet only eats the food we have recommended.


  • Any titbits or treats.
  • Dentastix or similar.
  • Kong treats.
  • Meaty flavoured tablets unless we have specifically recommended them.
  • Milk or dairy products.
  • Food dropped on the floor (shut dogs out when kids are eating).
  • Any other pets' food.

A typical food trial will last for at least 6 weeks. You do not need to introduce the new food slowly and can swap straight over to it, though with fussy pets it can help to slowly mix it with their old food.

The diet used for the food trial may not be the diet your pet stays on long term. It is only used to confirm your pet actually has a food allergy.

What do I feed my pet?

We are aiming to feed your pet something they have never eaten before, so their immune system is not already sensitised to it.

The most common dietary allergens are:

  • Chicken (turkey)                   
  • Beef
  • Dairy
  • Egg
  • Gluten

We will avoid these in any food trials we do. The exact trial we chose will depend on your pets' symptoms and history.

Homecooked food trial

  • Avoids contamination associated with processing plants.
  • Readily accepted by most pets.
  • Not suitable for cats unless using specific supplements as it can lead to heart disease.
  • Expensive.
  • Hard work.
  • May not be effective in pets with severe allergies.

A typical home cooked food trial would include boiled fish and potato, or venison and potato.

We do not recommend raw feeding due to the risk of contamination with Salmonella and Campylobacter, which could make you ill.

Shop bought food trial

These are single protein source diets that avoid the most common allergens.

  • Cheaper than the other options.
  • Available in lots of shops.
  • Wet and dry options.
  • Can be bland if dogs are used to highly processed, high fat foods.
  • May not be effective in pets with severe allergies.

When choosing a food stick to one flavour and read the back of the packet to make sure it doesn’t have any hidden chicken or “meat” in it. If you aren’t sure then call us and check it is suitable first. Do not always believe the advice of the shop workers!

Options for dogs:


  • James Wellbeloved Grain Free range.
  • Wainwrights Grain Free range.
  • Fishmongers.
  • Pooch and Mutt Grain Free.
  • Canagan (certain flavours).
  • Simpsons (certain flavours).


  • James Wellbeloved Grain Free range.
  • Wainwrights Grain Free range.
  • Canagan (certain flavours).
  • Simpsons (certain flavours).
  • Ardern Grange (certain flavours).
  • Natures Menu (certain flavours).

Options for cats:


  • James Wellbeloved Grain Free range.
  • Wainwrights Grain Free range.
  • Taste of the Wild (certain flavours).
  • Canagan Salmon.


  • James Wellbeloved Grain Free range.
  • Wainwrights Grain Free range.
  • Hi Life (certain flavours).

Prescription Diets

These are usually hydrolysed diets so the immune system can’t recognise the base protein used in their production.

  • The gold standard of diet trials.
  • Easily digested.
  • These can be bought from us or online.
  • Can be expensive in big dogs.

We most commonly recommend Purina HA because:

  • Based on hydrolysed soya so reactions are rare.
  • Low fat so good if your pet has weight issues or pancreatitis.
  • Comes in dry (dogs and cats) and wet (dog only).
  • Accepted by most pets.

If your pet has had a lot of soya or pea protein in their previous diet, we may instead recommend Royal Canin Anallergenic:

  • Base on hydrolysed feather protein so reactions are extremely rare.
  • Dry form only.
  • Less palatable than Purina HA.
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