According to Dr. Dou Phan, Deputy Head of the Department of Clinical Nutrition at Peking University People's Hospital, China , the antiviral effects of allicin in garlic have mainly been observed through animal or laboratory studies. Clinical evidence in humans is limited, therefore, consuming large amounts of garlic for therapeutic purposes should be avoided.
Garlic contains sulfur compounds, including allicin, which is formed when garlic is crushed or chopped. These compounds are being studied for their antioxidant properties and other biological effects. However, laboratory research results do not necessarily translate to efficacy in preventing or curing diseases in humans.
Therefore, those who like to eat garlic should use it as a seasoning in vegetable, meat, fish dishes, or sauces. They should not eat excessive amounts of raw garlic every day in the hope of boosting immunity, lowering blood cholesterol, or preventing cancer.
Raw garlic has a pungent taste and contains compounds that can irritate the digestive tract in some people. Eating large amounts of raw garlic can cause heartburn, acid reflux, abdominal pain, or discomfort, especially in people with sensitive digestive systems.