Here is a response from Master Herbalist Jared Tropple:

According to the National Foundation for Celiac Awareness you are scientiffically ok with using Wheatgrass. Some people, however, feel a discomfort from drinking wheatgrass because it is difficult for them to digest. By drinking it with a little ginger or pineapple juice you will digest it more easily.

Wheatgrass:
• Contains very high concentrations of vitamins, minerals and live enzymes
• is easy to grow
• is suitable for those on a gluten-free diet
• is an excellent provider of proteins required for cell regeneration and renowned for it’s healing properties
• Just 2 ounces of juice provides the same nourishment as up to 4 pounds of fresh, green vegetables
• helps to maintain healthy digestion, purify and build the blood, and is an excellent all round detoxifier
• is wonderfully energizing and very useful for helping in times of increased stress or illness.