Essiac tea is a mild dewormer and the rule was that you drink it 6 days a week for the rest of your life if you had a cancer.
It seems all yard grass is fine foods, I have tried all that grows in my yard and had zero ill effects. If your in the huge city, do not eat the grass, I suggest you have a container with country dirt in it or better yet, just use zero dirt and grow your own wheat grass or sprouts and you will do great. You will need distilled water to grow the sprouts/grass as well to live on. I use maple syrup and other herbs and minerals in the water to raise the grass/sproutsm also.
I have never lived in a city and to me a city is a few thousand people in my area. Your air quality would probably make me very ill until I could adapt.