Dogs know what they need
Dogs choose grass based on how it feels to them, the vibrations or the scents from it. In most cases it is fresh, greener grass that is eaten, with dogs specifically choosing one type or section.
Dogs do have an innate way of knowing what is going to help them, and what will not. There is in fact a science behind this innate sense, known as Zoo pharmacognosy, or sometimes Botanical Self-Healing.
Like almost all animals, dogs have a gland next to their scent gland called a VNO (Vomeronasal Organ). This organ is literally able to detect frequencies, so if a plant such as grass is fresh and vibrant, or of a variety they sense will be of use them, they will be attracted to it and want to eat it.
Why Do Dogs Eat Grass? Do They Feel Sick?
As mentioned already, the more vibrant and fresher the grass, the more your dog will be attracted to it as they can sense that grass better.
As predominantly carnivorous animals, dogs do not have a great ability to digest the cellulose of plants, especially in their raw state. If your dog is attracted to eating grass for a nutritional reason, they are still likely to bring it back up due to an inability to actually digest it.
Occasionally dogs will eat grass if they do genuinely feel nausea, however this is actually a rare event. It simply appears they felt nauseous because the grass is ‘bought back up again’ afterwards.
Believe it not they are not likely to actually be feeling sick and eating the grass because of that.
Some dogs can be seen eating grass almost on a daily basis, other dogs will only eat grass now and again.
Usually a dog will vomit the grass back up again, this is actually not ‘being sick’, in terms of nausea, it is a natural process called ‘regurgitation’.
It is the same as a dog eating too much bone, regurgitating it and then often eating it again. The regurgitation simply makes the bone or grass easier for them to digest the second time round.