Medicinal uses and health benefits of Garlic MCQs With Answer provide B.Pharm students a focused review of garlic’s phytochemistry, pharmacology, therapeutic applications and safety profile. Garlic (Allium sativum) contains organosulfur compounds such as allicin and S‑allyl cysteine that underlie its antimicrobial, antihyperlipidemic, antiplatelet, antioxidant and potential antihypertensive effects. Understanding preparation types (raw, oil, powder, aged extract), mechanism of action, stability issues, evidence strength and clinically relevant interactions is essential for rational herbal therapeutics and patient counseling. These MCQs reinforce key facts, mechanisms, formulations and adverse effects while linking pharmacognosy to clinical use. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which enzyme converts alliin to the biologically active allicin when garlic is crushed?
- Alliinase (alliin lyase)
- Peroxidase
- Lipase
- Amylase
Correct Answer: Alliinase (alliin lyase)
Q2. Which organosulfur compound is most directly responsible for the characteristic garlic odor and many pharmacological effects?
- Allicin
- S‑allyl cysteine
- Diallyl disulfide
- Alliin
Correct Answer: Allicin
Q3. Which garlic preparation is richest in stable water‑soluble sulfur compounds like S‑allyl cysteine and is used to reduce gastrointestinal irritation?
- Aged garlic extract
- Raw crushed garlic
- Garlic oil
- Fresh garlic powder
Correct Answer: Aged garlic extract
Q4. Crushing or chopping garlic increases formation of allicin because it releases which substrate from intact cells?
- Alliin
- S‑allyl cysteine
- Garlic oil
- Diallyl sulfide
Correct Answer: Alliin
Q5. Which mechanism best explains garlic’s mild antihypertensive effect observed in some clinical studies?
- Vasodilation via nitric oxide and hydrogen sulfide signaling modulation
- Direct beta‑adrenergic blockade
- Calcium channel blockade in cardiac tissue only
- Interference with renin synthesis in the kidney
Correct Answer: Vasodilation via nitric oxide and hydrogen sulfide signaling modulation
Q6. The lipid‑lowering effect of garlic is thought to involve which primary action?
- Inhibition of cholesterol synthesis and improved lipid metabolism
- Binding dietary cholesterol in the gut
- Increasing intestinal absorption of bile acids
- Direct stimulation of LDL receptor gene mutations
Correct Answer: Inhibition of cholesterol synthesis and improved lipid metabolism
Q7. Which adverse effect is most commonly reported with oral garlic supplementation?
- Garlic breath and gastrointestinal discomfort
- Nephrotoxicity
- Severe photosensitivity
- Ototoxicity
Correct Answer: Garlic breath and gastrointestinal discomfort
Q8. Which of the following drug interactions with garlic is clinically significant and requires caution?
- Increased bleeding risk with warfarin and other anticoagulants
- Marked reduction of insulin potency requiring discontinuation
- Potentiation of lithium toxicity through sodium loss
- Complete antagonism of ACE inhibitors
Correct Answer: Increased bleeding risk with warfarin and other anticoagulants
Q9. Heating garlic immediately after crushing reduces formation of which compound due to enzyme inactivation?
- Allicin
- S‑allyl cysteine
- Diallyl sulfide
- Vitamins
Correct Answer: Allicin
Q10. Which analytical marker is commonly used to standardize garlic supplements for pharmacological activity?
- Allicin yield or allicin potential
- Vitamin C content
- Total carbohydrate content
- Protein concentration
Correct Answer: Allicin yield or allicin potential
Q11. Which garlic constituent is water‑soluble, stable, and often measured in aged garlic extract?
- S‑allyl cysteine
- Allicin
- Alliin
- Garlic oil
Correct Answer: S‑allyl cysteine
Q12. Garlic exhibits antimicrobial properties primarily attributed to which action of allicin?
- Reaction with thiol groups in microbial enzymes leading to enzyme inactivation
- Disruption of microbial cell wall peptidoglycan synthesis only
- Lysis of microbial DNA helicase enzymes exclusively
- Chelation of essential metal ions in the host
Correct Answer: Reaction with thiol groups in microbial enzymes leading to enzyme inactivation
Q13. Which clinical indication has the strongest evidence base for garlic supplementation in adults?
- Modest reduction in total cholesterol and LDL cholesterol
- Complete remission of type 1 diabetes
- Herbal cure for metastatic cancer
- Cure for acute bacterial pneumonia
Correct Answer: Modest reduction in total cholesterol and LDL cholesterol
Q14. In pharmacognosy, which part of Allium sativum is used medicinally?
- Bulb (cloves)
- Roots only
- Flowers exclusively
- Stem bark
Correct Answer: Bulb (cloves)
Q15. Which statement about allicin stability is correct?
- Allicin is unstable and decomposes rapidly to other sulfur compounds
- Allicin is extremely stable and unaffected by heat
- Allicin is only produced during digestion in the stomach
- Allicin is a polysaccharide with long shelf life
Correct Answer: Allicin is unstable and decomposes rapidly to other sulfur compounds
Q16. Which preparation of garlic is least likely to cause gastrointestinal irritation and strong breath odor?
- Aged garlic extract
- Fresh crushed raw garlic
- Garlic oil swallowed whole
- Freshly chopped garlic consumed raw
Correct Answer: Aged garlic extract
Q17. Which pharmacokinetic property is true for many garlic organosulfur compounds?
- They are metabolized to multiple sulfur‑containing metabolites and rapidly excreted
- They accumulate unchanged in adipose tissue indefinitely
- They are excreted solely unchanged in feces
- They are not absorbed from the gastrointestinal tract
Correct Answer: They are metabolized to multiple sulfur‑containing metabolites and rapidly excreted
Q18. Which of the following is a recognized contraindication or precaution for high‑dose garlic therapy?
- Prior to surgery because of increased bleeding risk
- Concurrent use of topical corticosteroids only
- Simple seasonal allergic rhinitis without bleeding risk
- Mild common cold with no other medications
Correct Answer: Prior to surgery because of increased bleeding risk
Q19. Which biochemical assay could be used to evaluate in vitro antimicrobial activity of garlic extracts?
- Minimum inhibitory concentration (MIC) determination
- Amino acid sequencing
- Blood glucose assay
- Hemolysis test on red blood cells only
Correct Answer: Minimum inhibitory concentration (MIC) determination
Q20. Which statement best describes clinical trial evidence for garlic as an antihypertensive agent?
- Some trials show modest BP reduction, but results are variable and dose‑dependent
- All high‑quality trials show no effect on blood pressure
- Garlic causes consistent hypertensive crises in trials
- Garlic replaces need for antihypertensive drugs in all patients
Correct Answer: Some trials show modest BP reduction, but results are variable and dose‑dependent
Q21. Which laboratory parameter may be monitored in patients on warfarin who start garlic supplements?
- International Normalized Ratio (INR)
- Serum amylase
- Arterial blood gases
- Urinary protein excretion
Correct Answer: International Normalized Ratio (INR)
Q22. Which of the following best explains why raw garlic may have stronger immediate antimicrobial activity than aged garlic extract?
- Raw garlic produces allicin rapidly upon crushing, which has potent antimicrobial activity
- Aged garlic contains toxic solvents that inactivate microbes
- Aged garlic has higher sugar content that promotes microbes
- Raw garlic contains no sulfur compounds compared with aged extract
Correct Answer: Raw garlic produces allicin rapidly upon crushing, which has potent antimicrobial activity
Q23. Which organosulfur compound is typically used as a chemical marker for fresh garlic rather than aged garlic?
- Allicin
- S‑allyl cysteine
- Sugar alcohols
- Flavonoids
Correct Answer: Allicin
Q24. In development of a garlic‑based pharmaceutical, which stability concern is most critical?
- Allicin’s chemical instability and loss during processing and storage
- Protein denaturation at room temperature only
- Rapid polymerization into inert polysaccharides
- Complete conversion to vitamins over time
Correct Answer: Allicin’s chemical instability and loss during processing and storage
Q25. Which adverse dermatologic reaction has been reported with topical application of fresh garlic?
- Chemical burn and contact dermatitis
- Immediate tanning effect
- Permanent depigmentation
- Excessive hair growth
Correct Answer: Chemical burn and contact dermatitis
Q26. Which analytical technique is appropriate for quantifying allicin or sulfur compounds in garlic extracts?
- High‑performance liquid chromatography (HPLC) with suitable detectors
- Simple pH paper testing
- Colorimetric vitamin C strip only
- Microscopy of crushed cloves
Correct Answer: High‑performance liquid chromatography (HPLC) with suitable detectors
Q27. Which effect of garlic on platelet function has pharmacological relevance?
- Inhibition of platelet aggregation leading to antithrombotic potential
- Stimulation of platelet proliferation causing thrombocytosis
- Irreversible platelet destruction like antiplatelet drugs
- No effect on platelet function whatsoever
Correct Answer: Inhibition of platelet aggregation leading to antithrombotic potential
Q28. For a B.Pharm student studying herb‑drug interactions, which pharmacodynamic interaction with aspirin is important for garlic?
- Enhanced bleeding risk due to additive antiplatelet effects
- Aspirin completely neutralizes garlic’s odor
- Garlic inactivates aspirin via direct binding
- No interaction; both act on unrelated pathways
Correct Answer: Enhanced bleeding risk due to additive antiplatelet effects
Q29. Which traditional medicinal use of garlic is supported by modern pharmacological findings?
- Use as an antimicrobial and cardiovascular adjunct (lipid‑lowering/antiplatelet)
- Use as a hypnotic to induce deep sleep with no other effects
- Use as a local anesthetic for surgical procedures
- Use as a substitute for insulin in type 1 diabetes
Correct Answer: Use as an antimicrobial and cardiovascular adjunct (lipid‑lowering/antiplatelet)
Q30. Which safety counseling point should a B.Pharm student give to a patient starting garlic supplements?
- Inform healthcare providers about garlic use prior to surgery or when on anticoagulants
- Double the dose if no immediate benefit is noticed after one day
- Stop all prescription medications when taking garlic
- Use garlic exclusively to treat serious infections without antibiotics
Correct Answer: Inform healthcare providers about garlic use prior to surgery or when on anticoagulants
I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.
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