I had a sickly dog many years ago. He ate dirt. He only ate it from certain places and only ate a little, so I let him. Years after his death I realized he was sickly from over vaccination and poor diet and he was likely self medicating.
Since I have learned how to feed my dogs a real whole food diet I haven’t had a dirt eating dog.
Herbivores consume minerals outside of their food. They will find soils and salts to complete their diet. We need to supply mineral licks for our livestock, so it isn’t beyond belief that a malnourished carnivore might also crave minerals in the form of dirt.
There are certain clays that are helpful at expelling internal parasites and your dog may be self medicating that way. Soils can contain enzymes and beneficial bacteria that aid digestion.
If your dog is eating dirt or clay on a regular basis you need to check their diet first. But, I’m sure your asking, how about if I just keep doing what I’m doing and let my dog eat the dirt? Soils may contain pesticides or other toxic chemicals.
Eating clay or soil is symptom and an investigation is warranted if your dog is eating it consistently. Nutrient deficiency, internal parasites, or poor digestion can all make a carnivore crave dirt. Ask your local animal naturopath for guidance on providing a healthy species appropriate diet.