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Does Coffee Stunt Your Growth? Microbial Myths 6

March 23, 2026

Can coffee stunt your growth—or microbiome? We’re hitting a 100-myth milestone! From lizard blood to garden hacks and raw chicken, Michael Schmidt, Ph.D., debunks the wildest microbial urban legends.

Video Notes

Microbial Myths 6

We're back with the 6th edition of Microbial Myths, where we put microbial-related urban legends, superstitions and home remedies to the test! To date, we’ve tackled over 100 myths, from the commonly accepted to completely bizarre. Watch all the Microbial Myths and for hundreds of hours of microbiology videos.



In this 6th edition, Michael Schmidt, Ph.D., joined host Ashley Hagen, M.S., in the at 91Âé¶¹ÌìÃÀ Microbe 2025, to tackle nearly 20 additional microbial myths, making this more than 100 myths covered in this series! In this edition we cover myths including if dung ointment is an effective way to treat wound infections, if snail slime/mucus can cure skin infections, do dogs eat grass only when they’re sick, is lavender a good disinfectant and many more!

 

 Is Coffee good for your gut microbiome?

Verdict: 

True, in moderation. Coffee is a stimulant that has a lot of beneficial properties. When boiling water is added to coffee, essential oils are extracted, and those oils can feed the microbes in our small and large intestines. When introduced in the proper ratio and in conjunction with the proper diet, coffee can be beneficial for human health. But moderation is key! Less than 5 cups a day is recommended.

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Spraying baking soda on plants can cure diseases.

Verdict: 

True, particularly for fungal infestation. Baking soda raises the pH and makes the enviroment alkaline, inhibiting fungi, which grow best at room temperature, from assaulting your plants. Putting the baking soda on early, before the fungus can get a foothold on your plant leaf, is even better for the plant. However, once again, everything in moderation! Be careful not to overload the pH and raise it too high. Doing so may change the pH of the soil and limit plant growth. 

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Dung ointment is an effective way to treat wound infections.

Verdict: 

False. You don't know what is in the dung, unless it is a qualified dung donor. In fact, the fecal microbiome that you can actually buy as a pill comes from qualified donors, from whom the stool samples have been tested to ensure they are free of harmful microbes.

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Snail slime/mucus can cure skin infections? Stomach ulcers?

Verdict:

True. Mucin—the thing that the snail slides on—is a wonderful thing. Mucin has antimicrobial peptides in it, which can inhibit H. pylori, the causitive agent for ulcers

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Microbial Myths 6: True or False 

Interested in skipping to a particular myth to hear the verdict? Here is a list of timestamps to help you navigate the video:

  • Coffee and the gut microbiome.
  • Baking soda sprays for plant disease.
  • Dung ointment for wound infections.
  • Snail slime for ulcers.
  • Cold weather, hats and catching colds.
  • Lizard blood as an infectious disease remedy.
  • Dry noses and illness in pets.
  • Why dogs eat grass.
  • Ginger and periodontal disease.
  • Beeswax for jock itch and fungal infections.
  • Honey and beeswax for skin conditions.
  • Bleach on gardening tools to stop pathogens.
  • Washing raw chicken and food safety.
  • Does hot water clean better? 
  • Lavender as a disinfectant.
  • Colloidal oatmeal and chicken pox.
  • Zinc and the common cold.
  • Epsom salts for better tomatoes.
  •  Animals eating poop and nutrient deficiencies.

Author: Ashley Hagen, M.S.

Ashley Hagen, M.S.
Ashley Hagen, M.S. is the Scientific and Digital Editor for the American Society for Microbiology and host of 91Âé¶¹ÌìÃÀ's "Meet the Microbiologist" podcast.