Grass juice or any other green juice wont hurt you but puking and swelling up is a sign you should open up the bowels first.One should have a bowel movement for each meal!This can and should be done if you want to have maximum health and vitality.Life and death begin in the colon,grass juice dosent work if the pluming is sluggish.Read Dr. Norman Walkers "Become younger"this is a short read and a great place to start.Jeff.