Table 1.

Study characteristics.

Author year country	Study aim/objective	Definition of herbs/supplementary medications used – Definition source	Stakeholder involved (n)	% of herbs/supplementary medications users before vs during COVID-19	Reported specific herbs/supplementary medications used (%)	Reasons for using herbs/supplementary medications (%)
Teke et al.74 2021 Turkey	To analyze HCP's attitudes toward TCoM and life satisfaction due to COVID-19	•Traditional medicine: knowledge, skills, and practices that can or cannot be explained based on theories, beliefs, and experiences specific for different cultures used in maintaining health in addition to protecting from physical and mental diseases, diagnosing, healing, or treating these diseases. •Complementary medicine: health care practices which are not a part of the culture of that country's traditional medicine and which are not fully integrated to the dominant health system Source: World Health Organization	HCP (nurses, doctors, dentists, medical technicians, midwives, dieticians, and physiotherapists) n = 560	31.6% before 45.5% during	•Vitamin supplement (17.9%) •Ginger (17.8%) •Food supplement (15.3%) •Turmeric (9.9%) •Sumac extract (6.9%) •Black cumin (5.6%) •Royal jelly/propolis (5.6%) •Rosehip (5.3%) •Sage (4.4%) •Echinacea (0.5%) Wild angelica (0.1%)	•Strengthening the immune system (48.7) •Protect from illnesses (21.5) •Thinking that TCM methods are safe (14.8) •Psychological relaxation (11.3) •Hearing from people that it is beneficial (3.8)
d’Arqom et al.81 2021 Indonesia	To explore the mental health of mothers with school-age children, during COVID-19 and its relationship with the consumption of “anti-COVID” medications and supplements.	NP	General population: Mothers with school age children n = 610	NR	Natural products: •Ginger (31%), •Honey (30%), •Curcumin (22%) •Eucalyptus (5.0%) Vitamins/minerals •Vit C (39%) •multivitamins and minerals (32%) •Vit E (11%) •Vit D (8%), •Zinc (6%), Selenium (1%)	•To improve the immune system (88.4%). •To protect from fatigue (6.6%) •To reduce the disease symptoms (3.2%), •To support respondents' activity (1.2%) To kill SARS-CoV-2 (0.6%)
Kong et al.73 2021 Canada	To assess the attitudes towards the use of TCM in relation to Western medicine among Chinese immigrants in Canada during the early stage of the COVID-19 pandemic.	TCM encompasses a broad range of therapies, such as herbal medicine, acupuncture, massage, Qigong and dietary therapy Source: a review article87	General population: Chinese immigrants n = 754	NR	NR	NR
AlNajrany et al.70 2021 KSA	To investigate the use of prescription medications, awareness of the viral nature of COVID-19 infection and its common symptoms, and the commonly utilized herbal and/or dietary supplements.	NP are generally classified as DS and include products such as herbs, vitamins and minerals, and probiotics Source: National Center for Complementary and Integrative Health	General population n = 1473	NR	•Honey (46.1%), •lemon (45.2%), •Ginger (36%), •Vit C (32.5%), •black seed (26%), •garlic (25.8%) Others: mint, onions, Saussurea costus, thyme, clove solution, chamomile, cumin, moringa, and fennel (2.5%)	To boost immunity against the infection (64.0%)
Puścion-Jakubik et al.83 2021 Poland	To assess the knowledge and intake of FS during the COVID-19 pandemic, with particular focus on FS containing zinc and Vit D.	FS is a foodstuff intended to be a complement to a normal diet and is a concentrated source of nutrients (vitamins, minerals) or other substances with a nutritional or physiological effect. Source: European Food Safety Authority	General population n = 935	Before: NR 23.5% first COVID wave 25.6%, Second COVID wave 39.1% third COVID wave	Zinc and Vit D	NR
Mshana et al.68 2021 Tanzania	To explore the effects of COVID-19 on women and how the women and communities dealt with the threat of COVID-19, including the treatment practices	The term traditional medicine and local remedies are used interchangeably to refer to a wide range of herbal remedies in their various forms. This does not imply that these remedies originate in these communities, but there is exchange and adaptation of treatment paradigms between societies. Source: NR	General population: women between 27 and 57 years old n = 18	100% before 100% during	•Red onion (Allium cepa L.) •Garlic (Allium sativum L.) •Neem tree (Azadirachta indica. A.Juss) •Chili peppers (Capsicum frutescens L.) •Papaya (Carica papaya L.) •Lemon (Citrus limon L.) •Orange (Citrus sinensis L.) •Lemon grass (Cymbopogon citratus Stapf.) •Eucalyptus (Eucalyptus globulus Labill.) •Mango (Mangifera indica L.) •Ocimum canum L. •African basil (Ocimum gratissimum L.) •Elephant grass (Pennisetum purpureum) •Avocado (Persea americana Mill.) •Guava (Psidium guajava L.) •Castor (Ricinus communis L.) •Cloves (Syzygium aromaticum) •Tetradenia riparia (Hochst.) Ginger (Zingiber officinale)	•There is a strong belief that steaming and inhaling the steam of herbs protects against COVID
Alshammari et al.79 2021 KSA	To explore the beliefs and habits and the effect of the COVID-19 pandemic on DS consumption.	DS: substance intake by individuals to supplement the diet by increasing the total dietary consumption, concentrate, metabolite, constituent, extract, or combination of the preceding substances.” They includes vitamins, minerals, herbs, amino acids, and enzymes Source: FDA	General population n = 575	14.8% before 25.2% during 66% indicated no change in consumption due to COVID	DS vitamins and multivitamins (25.5%)	NR
Li et al.75 2021 China	To investigate the COVID-19 prevention knowledge and practices of supermarket staff, and the factors affecting their concerns about returning to work and to investigate attitudes toward preventing COVID-19 by means of TCM, the demand for related TCM products, and the feasibility of promoting TCM as an additional COVID-19 prevention measure.	NR	General population: supermarket staff n = 2309	NR	NR
Altun et al.77 2021 Turkey	To evaluate the dietary habits of the dietitians who had a leading role in this regard during the pandemic and their use of DS, functional food and HM.	•DS is defined as the useable forms of the amounts corresponding to high doses of vitamins and minerals and refers to supplements to the nutrients in our diet. •HM are defined as plants (such as leaves, roots and stems) and substances produced from one or more plants Source: Turkish Medical Association	HCP (dieticians) n = 550	42.4% used DS before 44.5% using HM during	Dietary supplements •Fish oil (81.9%), •Vit D (39.0%), •multivitamins (27.4%), •Probiotics (22.3%), •Vit C (19.4%), •black elderberry (17.4%), •Zn (15.8%), •Fe (10.3), •Vit B12 (5.2), •others: folic acid, Se, Ca, Mg, Betaglucan, propolis, CoQ10 (9.6%) Herbal medicine: •Nuts (78·9%) •Garlic (73·5%), •Herbal teas (57.5%) •Green tea (51.8%), Other: cauliflower–broccoli–cabbage (76·2%)	•Used DS to avoid COVID-19, (94·5%) •Used HM to avoid COVID-19, (46.1%) Used DS to lead a healthy life (41·6%)
Xia et al.71 2021 China	Use the theory of planned behavior to identify factors that affect the intention to use TCM.	NR	General population n = 10,824	NR	NR	NR
Alyami et al.76 2020 KSA	To explore the knowledge about COVID-19 preventive measures and their belief about the consumption of herbal products for the prevention of COVID-19 infection.	NR	General population n = 5258	Before: NR 22.1% during	•Vit C (94.4%) •Royal jelly (5.6%) Herbal products/food supplements (turmeric tea, ginger tea, garlic, onions, fish oil, ginseng, vinegar, sesame oil)	•To protect from COVID-19 (22.1%) Vit C was the most used DS to increase immunity and reduces the chance of contracting COVID-19
Pu et al.69 2021 China	To investigate the knowledge of HCP, their practices, and their attitudes toward TCM for the prevention and treatment of COVID-19 and then assess factors influencing their decisions.	NR	HCP (doctors and nurses) n = 401	59.4% reported using TCM in the past 5 years	NR	NR
Mohsen et al.82 2021 Lebanon	To assess the usage, knowledge and attitudes towards DS before and during the COVID-19 pandemic in Lebanon	DS is a non-drug product intended to supplement the diet with one or more of the following: vitamins, minerals, herbs, and amino acids Source: FDA	General population n = 2966	73.3% before 69.9% during	•Vit C (42.1%) •Vit D (41%) •Zinc (29.3%) •Multivitamins (28%) •Magnesium (26.1%) •Iron (25.0%) •Calcium (21.3%) •Vit B12 (21.1%) •Vit E (17.5%) •Vit A (16.5%) •Folic acid (16.1%) •Antioxidants (15.6%) •Phosphorus (12.0%) •Other vitamins (10.9%) •Herbal products (5.9%)	NR
Bhol et al.84 2021 International	To evaluate knowledge and attitude regarding immuno-nutrition in Indians residing in different parts of the world and to evaluate the food and nutrition based practices adopted during lockdown to boost immunity	NR	General population: Indians living across different countries n = 325	NR	•Citrus fruits/juice (87.4%) •Leafy vegetables (77.8%), •Turmeric water/milk (67.7%) •Vit C (56%) •Herbal tea (Cloves, cinnamon, black pepper, ginger and turmeric, holy basil, lemon, cardamom, carom seeds, tea leaves, Liquorice, fennel seeds and cumin seeds, mint, honey) (50.5%) •Multivitamins (47.4%) •Omega3 supplements (34.5%) •Zinc (28.9%)	To boost immunity by participants.
Alotiby et al.78 2021 KSA	To estimate the prevalence of using herbs and NP during the COVID-19 pandemic, determine reasons for using them, and evaluate their potential side effects.	NR	General population n = 1054	7.3% before 92.70% during	•honey (84%), •black seeds (63%), •lemons (54%), •ginger (41%), •garlic (31%), •turmeric (31%), •oranges (20%), •onions (17%). •chilli peppers (5%), •sesame oil (4%), and black pepper (3%).	•To improve their immunity but not as protection from the COVID-19 infection (69.3%) •To improve their general health, (17.2%) •To help alleviate COVID-19 symptoms, but not to cure the infection (8.7%) To both reduce the infection's symptoms and cure it (3.8%)
Karataş et al.72 2021 Turkey	To determine the use and belief about TCoM during the COVID-19 outbreak.	TCoM refers to therapeutic products and procedures that are not a part of conventional medical care, and are often used by patients without medical supervision Source: National Cancer Institute	General population n = 389	31.6% before 39.3% during	Herbal medicines (30.8%) •Aloe vera, Garlic, Ginkgo biloba, Senna, Ginseng, Cranberry, herbal tea, Glucosamine, Soy, others Nutritional supplements/vitamins (23.8%) Different multivitamins and minerals like calcium and iron, others	To prevent COVID-19 infection (39.3%)
Nguyen et al.80 2021 Vietnam	To examine the prevalence and indications for HM use, the factors associated with HM use, and Vietnamese peoples' attitudes towards HM.	NR	General population n = 508	NR	•Ginger (Zingiber officinale Rosc.) •honey (Mel) •garlic (Allium sativum L.) Perilla (Perilla frutescens (L.) Britt.)	•To treat sore throat (62.2%) •To treat cough (60.6%) •To treat nasal congestion (41.4%) To treat fever (35.7%)

HCP: Health care provider, NR: not reported KSA: Kingdom of Saudi Arabia; TCoM: traditional complementary medicine; TCM: Traditional Chinese Medicine; DS: Dietary supplements; HM: Herbal medicine; NP: natural products; FS: Food supplements; yrs: years.

*age as reported within the articles; Vit: Vitamin.