Common Side Effects

• Wheatgrass juice may cause headaches and stomach upset when people first begin drinking it. Alternative health practitioners attribute these effects to initial detoxification triggered by introducing wheatgrass into the diet.
  
  

Nausea

• People may become nauseated if they drink wheatgrass juice during a meal or soon afterward. The substance seems to cause less digestive trouble if taken on an empty stomach.
  
  

Diarrhea

• People also may experience diarrhea when they first start drinking wheatgrass juice, or if they drink too much of it.
  
  

Allergic Reaction

• People with an allergy or sensitivity to wheat should not drink wheatgrass juice or chew wheatgrass. Symptoms of an allergic reaction include a rash or hives, difficulty breathing, and throat or mouth swelling. People allergic to mold also may react to mold that can grow on wheatgrass.
  
  

Mold

• Wheatgrass can become contaminated by mold when grown outdoors. Indoor and outdoor growers debate whether this is a problem or not. Indoor growers of wheatgrass, such as the president of Perfect Foods, Inc., state that this mold does not cause harm to humans, and that it can easily be cut away or rinsed off before juicing.