The scientific name of holy basil is Ocimum tenuiflorum.
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.)
Claims for Holy Basil
Advocates believe that holy basil is an adaptogen. 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
Evidence for Holy Basil
Any single compound, including holy basil, is highly unlikely to have such a broad range of health benefits. Thus, evidence is very unlikely to confirm such multiple benefits. There are no high-quality studies in people demonstrating that holy basil is effective for treating any health condition.
Studies in animals suggest that holy basil seed oil might do the following:
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
But none of these findings has been replicated in people.
The evidence from studies in people to show that holy basil has health benefits is limited. Many of these studies are small and of poor quality. These studies show that holy basil could have the following health benefits, among others, but larger studies with better designs are needed to confirm these preliminary findings:
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
Side Effects of Holy Basil
Holy basil seems to be safe for most people when taken by mouth for up to 8 weeks. But holy basil can have side effects, such as nausea or diarrhea.
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 in the blood, so it could worsen hypothyroidism.
Holy basil could increase the risk of bleeding during and after surgery because it might slow down blood clotting.
Drug Interactions with Holy Basil
Holy basil may lower blood sugar and thus possibly result in hypoglycemia
Recommendations for Holy Basil
Holy basil is not recommended because the claimed health effects have not been confirmed in high-quality studies in people.
Holy basil is probably safe for most people; however, the following precautions should be observed:
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 medications (including medications to slow blood clotting or decrease blood sugar) should talk to their doctor before taking holy basil.
