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  • Writer's pictureNaghmeh Mirhosseini

Whitania Somnifera (Ashwagandha)

Other names: Ashwagandha, Indian Ginseng, Winter cherry

Plant Family: Solanaceae or nightshade family that grows in India, the Middle East, and parts of Africa. The roots are the main portion of the plant used therapeutically. The bright red fruit is harvested in the late fall and seeds are dried for planting in the following spring. The berries have been shown to have an emetic effect.

Active compounds: The major biochemical constituents of ashwagandha root are steroidal alkaloids and steroidal lactones, called withanolides. There are over 12 alkaloids and 35 withanolides, isolated from the plant. Much of ashwagandha’s pharmacological activity is attributed to the two main compounds, withaferin A and withanolide D.

Mechanism of action: The withanolides act as a hormone precursor which can be converted into human physiologic hormones as needed. In an excess hormone condition, Ashwagandha occupies cell membrane receptors so the actual hormone cannot attach and be functional. If the hormone level is low, it exerts a small effect. Ashwagandha is also an adaptogen and antioxidant, facilitating body’s ability to withstand stressors. It improves the body's defense against disease by improving the cell-mediated immunity. With its potent antioxidant properties, Ashwagandha helps protect against cellular damage caused by free radicals.

Medicinal properties: adaptogen, liver tonic, anti-inflammatory agent, immune stimulant, astringent, aphrodisiac, hypoglycemic, diuretic, hypocholesterolemic, chemo-preventive, antimicrobial and antifungal activity

Clinical application:

  • To help reduce stress and may also reduce stress-related weight gain.

  • To improve sleep in patients with insomnia or non-restorative sleep.

  • To treat bronchitis, asthma, ulcers, senile dementia, other neurological disorders, anxiety, depression, and Parkinson’s disease.

  • To help improve sexual arousal and satisfaction in some females with sexual dysfunction.

  • To protect cardiovascular system

  • To treat hypothyroidism through its thyrotrophic effects

  • To reduce tumor growth, through generating cytotoxic T lymphocytes

  • To improve quality of life and decrease chemotherapy-induced fatigue in cancer patients

Dosage: A typical dose of ashwagandha is 3-6 grams daily of the dried root, 300-500 mg of an extract standardized to contain 1.5 percent withanolides, 2-4 ml of tinctures or 6- 12 ml of a 1:2 fluid extract per day.

Side effects and toxicity: Ashwagandha is generally safe when taken in the prescribed dosage range. Continuous consumption for over 3-6 months increases the risk of adverse effects. Large doses may cause gastrointestinal upset, diarrhea, nausea and vomiting and rarely dermatitis, jaundice, pruritus and liver problems.

Herb-Drug interaction:

  • Ashwagandha can increase the activity of the immune system. So, it interacts with immunosuppressants and might decrease the effects of these medications.

  • Ashwagandha and sedatives (Benzodiazepines) both may cause sleepiness and slow breathing. Taking ashwagandha with sedative medications might cause breathing problems or too much sleepiness.

  • Ashwagandha might increase thyroid hormone production in the body, which interacts with the thyroid hormones naturally producing in the body. Taking ashwagandha with thyroid hormone pills might hyperthyroidism symptoms.

  • Ashwagandha may lower blood sugar levels. Taking ashwagandha with diabetes medications might cause blood sugar to drop too low.

  • Ashwagandha may lower blood pressure. Taking ashwagandha with medications that lower blood pressure might cause blood pressure to go too low.


  • Large doses of ashwagandha may be abortion inducer; therefore, it should not be taken during pregnancy. There is some evidence that ashwagandha may cause miscarriages.

  • There is no reliable information if ashwagandha is safe during breastfeeding, so it is better to avoid use.

  • Ashwagandha stimulates immune system and might increase the symptoms of autoimmune diseases like lupus, multiple sclerosis and rheumatoid arthritis. it's best to avoid using ashwagandha with these diseases.

  • Ashwagandha may slow down the central nervous system. So, it may interact with anesthesia and other medications during and after surgery. It is recommended stop taking ashwagandha at least 2 weeks before a scheduled surgery.


Natural Medicine, Ashwagandha []

Ashwagandha, WebMed. []

Withania Somnifera, Alternative Medicine Review 2004; 9(2): 211-14 []

Bluementhal M. HerbClip, Ashwagandha Monograph. 1999. []

Ashwagandha, [ monographs/ns/ashwagandha.html]

Health Canada, Ashwagandha Monograph []

Vaishnavi K, Saxena N, Shah N, et al. Differential activities of the two closely related withanolides, Withaferin A and Withanone: bioinformatics and experimental evidences. PLoS One. 2012;7(9):e44419.

Biswall BM. Et al. Effect of Withania somnifera (Ashwagandha) on the development of chemotherapy-induced fatigue and quality of life in breast cancer patients. Integr Cancer Ther. 2013;12(4):312-322.

Biswall BM. Et al. AOS14 Phase II clinical study of combination chemotherapy with herb Withania somnifera (ashwagandha) in breast cancer. Eur J Cancer. 2012;48(var.pagings):S8-S9.

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