Garlic kill 14 types of bacteria

Yes. Garlic (Allium sativum) has demonstrated antibacterial activity against many types of bacteria, mainly because crushing fresh garlic produces allicin, a sulfur-containing compound with antimicrobial activity. However, it is more accurate to say garlic can inhibit or kill bacteria under laboratory conditions, rather than claiming that eating garlic will “kill” these bacteria inside the human body. PPubMed Central (PMC)+1

14 bacteria affected by garlic

1. Escherichia coli (E. coli)

   • Some strains of E. coli can cause diarrhea, urinary-tract infections, and other illnesses.

   • Garlic extracts and allicin have shown inhibitory activity against E. coli, including some enterotoxigenic and multidrug-resistant strains.

   • Allicin interferes with bacterial enzymes containing reactive thiol (-SH) groups. PPubMed Central (PMC)+1

2. Staphylococcus aureus

   • A Gram-positive bacterium associated with skin infections, wound infections, pneumonia, and bloodstream infections.

   • Garlic extract and allicin have demonstrated antibacterial activity against S. aureus.

   • Importantly, laboratory studies have also found activity against MRSA (methicillin-resistant S. aureus). PPubMed Central (PMC)+1

3. Salmonella enterica

   • Includes bacteria responsible for salmonellosis and foodborne illness.

   • Garlic preparations have shown inhibitory activity against Salmonella in laboratory studies.

   • Allicin can interfere with essential bacterial proteins and enzymes. PPubMed Central (PMC)+1

4. Salmonella Typhimurium

   • A specific serotype of Salmonella that can cause gastroenteritis.

   • Pure allicin has demonstrated growth-inhibiting activity against this organism in experimental systems. PPubMed Central (PMC)

5. Pseudomonas aeruginosa

   • An opportunistic Gram-negative bacterium that can cause serious infections, particularly in people with certain underlying conditions.

   • Garlic extracts and organosulfur compounds have shown antibacterial activity against P. aeruginosa in vitro. PPubMed Central (PMC)+1

6. Klebsiella pneumoniae

   • Can cause pneumonia, urinary infections, bloodstream infections, and other infections.

   • Studies have reported inhibitory effects from garlic extracts, including activity against some multidrug-resistant isolates. PPubMed Central (PMC)

7. Helicobacter pylori (H. pylori)

   • This bacterium colonizes the stomach and is associated with gastritis and peptic ulcers.

   • Allicin and garlic preparations have demonstrated activity against H. pylori in laboratory/preclinical research.

   • Important: garlic should not be considered a replacement for standard H. pylori eradication treatment; clinical evidence does not show that simply consuming fresh garlic reliably eradicates the infection. PPubMed Central (PMC)+1

8. Streptococcus mutans

   • An important bacterium involved in dental plaque and tooth decay.

   • Garlic extracts have shown antibacterial activity against S. mutans in laboratory studies. PPubMed Central (PMC)+1

9. Streptococcus pyogenes

   • Can cause strep throat, skin infections, and other illnesses.

   • Garlic preparations have demonstrated inhibitory activity against this bacterium in vitro. PPubMed Central (PMC)+1

10. Enterococcus faecalis

    • Normally found in the gastrointestinal tract but can cause urinary, wound, and bloodstream infections.

    • Allicin has shown activity against Enterococcus species, including some strains with resistance to conventional antibiotics. PPubMed Central (PMC)

11. Bacillus subtilis

    • A Gram-positive bacterium commonly used in laboratory research.

    • Aqueous garlic extracts have demonstrated antibacterial activity against B. subtilis. PPubMed Central (PMC)+1

12. Bacillus cereus

    • Can cause food poisoning, particularly through contaminated foods.

    • Garlic extracts and garlic powder have demonstrated inhibitory activity against B. cereus in experimental studies. PPubMed Central (PMC)

13. Shigella species

    • Shigella can cause shigellosis, an intestinal infection characterized by diarrhea and sometimes bloody stools.

    • Garlic extracts have demonstrated antibacterial activity against Shigella species in laboratory studies. PPubMed Central (PMC)+1

14. Vibrio cholerae

    • The bacterium responsible for cholera.

    • Pure allicin isolated from garlic has demonstrated growth-inhibitory activity against V. cholerae experimentally. PPubMed Central (PMC)

How does garlic kill bacteria?

The major mechanism involves allicin:

Crush/chop garlic → alliin + alliinase react → allicin forms

Allicin is highly reactive and can enter bacterial cells. It reacts with cysteine/thiol groups on important bacterial proteins and enzymes, disrupting processes required for energy production, metabolism, redox balance, and growth. PPubMed Central (PMC)+1

This is why freshly crushed garlic is particularly interesting scientifically: allicin is generated when the garlic tissue is damaged. Heating and processing can substantially change the amount and composition of these sulfur compounds. PPubMed Central (PMC)+1

One important caution

These findings do not mean that eating garlic will cure bacterial infections. Much of the evidence comes from test-tube/agar experiments, and the concentration of allicin that inhibits bacteria in a laboratory may not be achievable at the site of infection by eating garlic. Garlic can be part of a healthy diet, but diagnosed bacterial infections may require appropriate antibiotics or other medical treatment. PPubMed Central (PMC)+1

If you want, I can also give you a table of 20–30 bacteria affected by garlic, including Gram-positive/Gram-negative classification and the infection each can cause.