Are Dandelions as Effective as Commonly Prescribed Antibiotics Against Bacteria?

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Updated on Jan 29, 2014


To determine whether dandelion roots, which are used in many parts of the world for therapeutic purposes, can be used as an antibiotic against the bacteria Serratia marcescens and Escherichia coli, and to determine whether they are as effective as commonly prescribed antibiotics.

Materials Needed

  • Dandelion roots
  • Food processor
  • Cheesecloth
  • 5 cups
  • Sterile distilled water
  • Dandelion capsules (can be obtained from a health food store)
  • Sterile pin
  • Penicillin tablets (250 mg) (can be obtained from a medical doctor)
  • Erythromycin tablets (250 mg) (can be obtained from a medical doctor)
  • Tetracycline tablets (250 mg) (can be obtained from a medical doctor)
  • Sterile applicators
  • 12 petri dishes: tryptic soy agar with 5% sheep's blood
  • Serratia marcescens culture
  • Escherichia coli culture
  • Masking tape
  • Marking pen
  • Incubator
  • Forceps
  • Sterile filter paper disks


Tests will be carried out to determine whether dandelion roots can be used as effective antibiotics. Dandelion roots taken directly from the ground as well as dandelion root capsules will be tested on selected bacteria to see if they have any effect. Control tests will also be conducted using three common antibiotics as well as distilled water on the same bacteria. The results of both tests will be analyzed and compared.


Part I—Prepare the dandelion and the antibiotic tablet solutions.

  1. Thoroughly wash several dandelion roots and pulverize them in the food processor until they are liquefied.
  2. Filter the liquefied roots through the cheesecloth and into a sterile cup. Add enough distilled water to the liquid to form a one-to-one ratio.
  3. Pierce one dandelion capsule with a sterile pin and squeeze the contents into another cup holding ½ cup (0.12 liter) of distilled water.
  4. Dissolve one penicillin tablet in ½ cup (0.12 liter) of water. Similarly, dissolve one Erythromycin and one Tetracycline tablet separately into ½ cup (0.12 liter) of water.

Part II—Test the solutions on the bacteria strains.

  1. With a sterile applicator, streak six tryptic soy agar (TSA) petri dishes with the Serratia marcescens. With another sterile applicator and six TSA petri dishes, repeat this procedure with the Escherichia coli. Label the dishes and incubate them for 48 hours at 95 degrees Fahrenheit (35 degrees Celsius). Carefully note the growth of bacteria in each dish.
  2. Using the forceps, dip a sterile filter paper disk into the dandelion root solution and place it onto one of the petri dishes containing S. marcescens. Dip another sterile filter paper disk into the dandelion capsule solution and place it onto the second petri dish containing S. marcescens. Continue this procedure by placing sterile filter paper disks soaked in the three antibiotic solutions onto the next three petri dishes containing S. marcescens. Place a sterile filter paper disk soaked only in sterile distilled water onto the remaining dish containing S. marcescens. Label all dishes accordingly.
  3. Repeat step 2 with those dishes containing E. coli.
  4. Incubate all the petri dishes for 48 hours at 95 degrees Fahrenheit (35 degrees Celsius). Carefully note the amount of bacteria in each dish and compare those results against the amount of bacteria found in each dish before it was treated. Compare the amount of bacteria between those dishes treated with the dandelion solutions to those treated with the antibiotic solutions and the untreated dishes. Record your observations.


  1. Were either the dandelion root or capsule solutions effective in inhibiting bacterial growth? If so, did their effectiveness vary with the type of bacteria used? Was one dandelion solution more effective than the other?
  2. Were the antibiotic tablets successful in inhibiting the growth of the bacteria used in the experiment?
  3. How did the dandelion solutions compare to the antibiotic solutions?