Medicines & Supplements A to Z > Garlic (Supplement)

Garlic (Supplement)

Last updated on 22/03/2021.

Overview   |   Dosage   |    Side Effects   |   Precautions  |   Tips  |   Where To Buy  

GENERIC NAME: Garlic / Allium sativum


BRAND NAME(S) IN HONG KONG: Doctor’s Choice 醫之選, Now Foods

DRUG CLASS: Herbal medicine 

USED FOR: Reduction of high cholesterol level, antiplatelet effects, prevention of common colds, protection against cancers

OTHER DRUGS IN THE SAME CLASS: Asian Ginseng, Chamomile, Coenzyme Q10, Cranberry, Echinacea, Ginkgo Biloba, Kava, St John’s Wort, Valerian

AVAILABLE DOSAGE FORMS: 1000mg, 2000mg, 5000mg (softgels)

What is Garlic for?

Garlic is a plant that can be taken as a supplement. The active ingredient in Garlic that can give health benefits is called allicin. It can help lower the level of bad cholesterol (LDL) and has antiplatelet effects. It hence can be used as a supplement if you have high cholesterol or high blood pressure. There are also claims saying that Garlic might help prevent common colds and cancers. Still, there is limited scientific evidence to support these claims.

How to use it?

Garlic supplements are taken by mouth in the form of tablets or capsules. The usual adult dose is 300-1000 mg. For specific dosages, refer to the product label.

What are the side effects of Garlic?

Side effects of Garlic as supplement include heartburn, stomach upset, breath and body odor, headache and dizziness. Garlic might also increase the risk of bleeding. Advise your doctor or pharmacist before taking a Garlic supplement if you are currently taking any antiplatelet drugs (e.g. Aspirin, Clopidogrel) or anticoagulant drugs (e.g. Warfarin) as it can increase bleeding risks.

Who should not take Garlic?

Patients with a bleeding disorder should avoid Garlic supplements as Garlic may increase the risk of bleeding.

Pharmacist Tips:

Data on the safety and efficacy of Garlic are limited and not robust. There is also variability in the quality and purity of the products. Always consult your doctor or pharmacist before taking any herbal supplements.

Common dosing schedule:
Take Garlic supplements as per product instructions.

This schedule is for reference only, adjustments may be made according to individual needs.

Some common medications Garlic may interact with:
Anticoagulants, e.g. Heparin, Warfarin
Antiplatelets, e.g. Aspirin, Clopidogrel
Other herbs that may increase the bleeding risk, e.g. Ginger, Ginkgo Biloba, Ginseng

Please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Garlic in Hong Kong?

In Hong Kong, Garlic supplements can be purchased without a prescription from any retail outlet in Hong Kong. This includes grocery stores, convenience stores, medicine shops, and pharmacies. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.

For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at

Need more information?

For detailed information about the use of Garlic in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.