Holy Basil - Special Subjects - Merck Manuals Consumer Version (2024)

• The Hindu name for holy basil is tulsi, which means the incomparable one.

• Other names for this plant are Thai basil and brush-leaf tea.

• Holy basil is a plant that is native to India but also grows in Australia, West Africa, and some Middle Eastern countries.

• This herb has been used for more than 3,000 years as part of Ayurvedic medicine in India.

• Hindus view holy basil as a sacred plant, and they often plant it around Hindu shrines.

• Medicine is made from the leaves, stems, and seeds of holy basil plants.

• Some people use holy basil in cooking (and it is sometimes called "hot basil" in cookbooks) because of its bitter, spicy taste.

• Holy basil is available in dietary supplements in the form of pills and capsules, and its essential oil is distilled from the plant's leaves and flowers.

(See also Overview of Dietary Supplements Overview of Dietary Supplements Dietary supplements are used by about 75% of Americans. They are the most common therapies included among integrative medicine and health (IMH) and complementary and alternative medicine (CAM)... read more .)

Advocates believe that holy basil is an adaptogen Adaptogens "Adaptogen" is a term for certain foods and supplements that are said to help the body cope with "stress." Stress may be psychologic (in the mind), but also may be physical (in the body), and... read more . This herbal medicine term means that this substance is thought to help the body respond to stress and restore normal function. Other uses of holy basil are to:

• Reduce anxiety and stress

• Lower blood sugar in people with diabetes

• Lower cholesterol levels

• Provide protection from bacterial and viral infections

• Promote wound healing

• Reduce inflammation

• Prevent ulcers and changes in the heart and blood vessels due to stress

• Slow the growth of cancer cells and lengthen survival in animals with cancer

• Reduce anxiety

• Reduce plaque and gingivitis in the mouth when taken as a leaf extract in a mouthwash

• Reduce anxiety and relieve the stress and depression that accompany anxiety

• Decrease blood sugar levels

• Decrease symptoms of stress (for example, sleep problems, exhaustion, forgetfulness)

• Improve breathing function and reduce attacks in people with asthma

• Improve the immune system's response to viral infections

• Reduce inflammation and joint pain

• The safety of taking holy basil for longer than 8 weeks has not been studied.

• Holy basil might not be safe when taken by women who are pregnant or trying to become pregnant. In animal studies, large doses of holy basil reduced the chance that a fertilized egg would become attached to the uterus and that the pregnancy would last for a full term. Whether these effects happen in humans is not known.

• The safety of holy basil in women who breastfeed their babies has not been studied.

• Holy basil might decrease levels of the thyroid hormone thyroxine, so it could worsen hypothyroidism Hypothyroidism Hypothyroidism is underactivity of the thyroid gland that leads to inadequate production of thyroid hormones and a slowing of vital body functions. Facial expressions become dull, the voice... read more (low levels of thyroxine).

• Holy basil could increase the risk of bleeding during and after surgery because it might slow down blood clotting.

Holy basil may lower blood sugar and thus possibly result in hypoglycemia Hypoglycemia Hypoglycemia is abnormally low levels of sugar (glucose) in the blood. Hypoglycemia is most often caused by medications taken to control diabetes. Much less common causes of hypoglycemia include... read more when combined with some antihyperglycemic (glucose-lowering) drugs such as insulin or sulfonylureas (such as glimepiride).

• Pregnant and breastfeeding women, women who are trying to become pregnant, and people with type 2 diabetes, hypothyroidism, and those undergoing surgery should avoid holy basil.

• People who take certain drugs (including drugs to slow blood clotting or decrease blood sugar) should talk to their doctor before taking holy basil.