If you Google "wheatgrass", the first link that appears is one to Wikipedia. After that is a site called Wheatgrass Kits.com, which has a handy-dandy section called "40 Benefits of Wheat grass".
Forty is a lot, so I'll break this into several posts. Let's take a look at these claims.
1 Wheatgrass Juice is one of the best sources of living chlorophyll available.
Alright, nothing really wrong here. We may not know what living chlorophyll is and why it's good for us, but we can give them the benefit of the doubt that wheatgrass has a lot of it.
2 Chlorophyll is the first product of light and, therefore, contains more light energy than any other element.
Hm. What is light energy? A Wikipedia search for "light energy" doesn't turn up any responses. A Google search for the term leads to articles regarding the physics of light and energy, but nothing about the term "light energy".
3 Wheatgrass juice is a crude chlorophyll and can be taken orally and as a colon implant without toxic side effects.
So the good news is that it's not poisonous. You can even stick it up your bum if you like. This doesn't mean it will do anything good for you, but it won't do anything bad.
4 Chlorophyll is the basis of all plant life.
This is absolutely true. Unfortunately, I am not a plant.
5 Wheatgrass is high in oxygen like all green plants that contain chlorophyll. The brain and all body tissues function at an optimal level in a highly-oxygenated environment.
Fortunately, we have lungs to provide our brain and body tissues with oxygen. If you think you may not be getting enough oxygen, you can always buy yourself a can. Try doing some Calculus after, I'll be interested to hear how that goes for you.