Plants – Poinsettia


  • Poinsettias are indigenous to Mexico and Central America and have large red leaves. 
  • Poinsettias are a prevalent plant during the holidays, especially at Christmas. Alternate names for Poinsettias ar:
    • Euphorbia
    • lobster flower
    • flame leaf flower
    • Flower of the Holy Night 
    • flower of Christmas Eve
    • Crown of the Andes
    • Easter flower

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  • Most people grow up believing that Poinsettias are poisons plants most likely due to a false theory of a young child found dead clutching a Poinsettia leaf in her hand back in 1919. A study conducted at Ohio State University has proven that Poinsettias are not poisonous to humans to pets.

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  • Toxicity of poinsettias have been studied using animal models and these studies have revealed little to no toxicity. 
  • one study could not find a lethal dose 50 in rats
  • at the highest dose orally administered, there was no evidence of any symptoms during a 14-day observation. 
  • there was minor skin irritation with repeated dose exposure in rabbits. 



  • Nearly all patients do not require any therapy and can be treated without going to the hospital. 
  • When coming in contact with poinsettia it is not recommended to vomit, decontaminate and the use of dilution. 
  • Supportive care through symptomatic management, such as antiemetics, is the only recommendation. 



    • Mild, itchy rash with contact with the sap of a poinsettia
    • A mild stomachache, vomiting or diarrhea after eating part of a Poinsettia
    • Eye irritation if the sap of a Poinsettia comes in contact with the eye
    • Allergic reaction. more common with people with latex allergy but differs from person to person.




  1. Evens Z., Stellpflug S. (20120. Holiday Plant with Toxic Misconceptions. Regions Hospital Toxicology Education and Clinical Services. Retrieved from:
  2. Jay L. Hoecker, M.D. “Poinsettia Plants: Are They Poisonous?” Mayo Clinic, Mayo Foundation for Medical Education and Research, 8 Oct. 2019,
  3. “Poinsettia Are Toxic To Pets.” Pet Poison Helpline,
  4. “Poison Poinsettias, Are They Toxic? Myth or Fact?” Fresh Flower Delivery,

Solvents – Propylene Glycol


Berg, Eric, director. Propylene Glycol Side Effects & Dangers by Dr.Berg. YouTube, YouTube, 1 Aug. 2018,

  • The video above explains the variety of uses of propylene glycol. FDA recognizes propylene glycol as generally safe, and humans are typically exposed through ingestion of food and skin contact with cosmetic or topical medications. Propylene glycol is also found in many pharmaceuticals, including:
      • phenytoin
      • diazepam
      • lorazepam



  • If too much propylene glycol is ingested over a short period, iatrogenic propylene glycol overdose can cause the following (2):
      • Hyperosmolaity and an anion gap metabolic acidosis
      • Refractory hypotension
      • Arrhythmias
      • Hemolysis
      • Renal dysfunction
      • Seizure
      • Coma 
  • Children may also experience CNS depression and seizures (2). 



  • Propylene glycol is absorbed rapidly from the gastrointestinal tract. The plasma concentrations in humans occur 1 hour after ingestion. The liver metabolizes propylene glycol by alcohol dehydrogenase into lactic acid and pyruvic acid, which are further metabolized into carbon dioxide and water (2).

Jeffrey A. Kraut, Ira Kurtz Toxic Alcohol Ingestions: Clinical Features, Diagnosis, and Management CJASN Jan 2008, 3 (1) 208-225; DOI: 10.2215/CJN.03220807



  • No adverse effects have been found with the normal use of pharmaceuticals containing propylene glycol. Prolonged or extensive topical application can cause excess propylene glycol levels in your body (3). 
  • Foods containing propylene glycol have shown a remarkably consistent low toxicity hazard, demonstrated with acute, short term, and chronic exposures studied on animal models (2). 
  • Human systematic toxicity (2):
    • Virtually unknown with normal propylene glycol levels. 
    • Acute ingestion or intravenous intoxications involving extremely high doses in critically ill or susceptible patients can show toxicity. Even in these extreme cases, complete recovery is expected. However, transient signs of altered nervous system function (commonly observed with short-chain glycol exposure) may occur with exposure to high doses.



  • The main target organ affected by propylene glycol poisoning is the kidneys (2). The hyperosmolality is often accompanied by acute kidney injury leading to multi-system organ failure (2). Additionally, increased serum creatinine concentrations and proximal renal tubular cell injury distinguish renal dysfunction of some propylene glycol poisonings (2).




  1. Berg, Eric, director. Propylene Glycol Side Effects & Dangers by Dr.Berg. YouTube, YouTube, 1 Aug. 2018, 
  2. “Ethylene Glycol and Propylene Glycol Toxicity: What Is Propylene Glycol?” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 7 Oct. 2020,
  3. Fowles JR, Banton MI, Pottenger LH. A toxicological review of the propylene glycols. Crit Rev Toxicol. 2013 Apr;43(4):363-90. doi: 10.3109/10408444.2013.792328. PMID: 23656560. 
  4. Jeffrey A. Kraut, Ira Kurtz CJASN Jan 2008, Toxic Alcohol Ingestions: Clinical Features, Diagnosis, and Management3 (1) 208-225; DOI: 10.2215/CJN.03220807

Metals – Mercury


Mercury has been used for medications and is also found in many products that can cause toxicity to our bodies. Many know that the main consumption of mercury for humans is through seafood, but it is also found in vaccines to infants, dental amalgams, and some prescription medications.


Mercury ions produce protein precipitation, enzyme inhibition, and corrosive action through their binding to sulfhydryl groups.


Absorption of mercury into our bloodstream accounts for 90% of mercury binding to our red blood cells and 10% of mercury binding to our plasma cells. Humans that consume large amounts of mercury daily it was found that inorganic mercury was found in the whole blood (7%), plasma (22%), breast milk (39%), liver (16-40%) and urine (73%). Methylmercury is completely absorbed from our GI tract, distributed to the brain, liver, and kidney. Excretion is primarily in the feces.




Mercury has been around for many centuries and used in scientific research. One example would be the use of mercury in thermometers. While these types of thermometers are no longer in use in the health care sector, China still produces several devices that contain mercury.



Broussard, Larry, et al. “The Toxicology of Mercury.” LSU Health Sciences Center, 2021,

Czaika, Ellen, et al. Mercury Science and Policy at MIT, 15 Jan. 2013,

National Research Council (US) Committee on the Toxicological Effects of Methylmercury. Toxicological Effects of Methylmercury. Washington (DC): National Academies Press (US); 2000. 2, CHEMISTRY, EXPOSURE, TOXICOKINETICS, AND TOXICODYNAMICS. Available from:

Pesticides – Picaridin


As we approach the warmer summer months, bug spray is the perfect way to enjoy the outdoors by keeping the mosquitoes, flies, ticks, fleas, and triggers away. As an alternative to DEET, a newer form of bug spray contains the chemical picaridin, an insect and acarid repellent in the piperidine chemical family.

The history of picaridin goes back to when it was first developed in the 1980s by Bayer, and the EPA later registered it in 2001. It wasn’t until 2005 that it was first approved for use in the United States. The chemical name for picaridin is 1-piperidine carboxylic acid 2-(2-hydroxyethyl)-1-methylpropylester.


How does picaridin work to repel insects? The insects detect the chemical sprayed on your skin or clothing through their olfactory sensing consisting of odorant receptors that need a common co-receptor and ionotropic receptors, leading to the insect’s inability to recognize its host’s cues. Researchers studied how mosquitoes respond to picaridin and found that the chemical stimulates sensory hairs on the mosquito’s antennae. This appears to prevent the mosquito from recognizing its host’s cues.

For humans, picaridin has limited dermal absorption and is metabolized via hydroxylation and glucuronidation. It is excreted in the urine.



The toxicological profile of picaridin is classified as slightly toxic if ingested. The U.S. EPA considered picaridin to be slightly toxic for acute dermal and ocular exposure. Picaridin is not considered a skin irritant and is not a sensitizer, but it can cause slight to moderate eye irritation and practically non-toxic for inhalation exposure. Additionally, there is no evidence of genotoxicity, carcinogenicity, teratogenicity, reproductive toxicity, or neurotoxicity. Below you can find a chart from the National Pesticide Information Center of the different toxicology classifications.


  • Dermal irritation on human subjects following application of 20% picaridin aerosol, 20% picaridin lotion, or technical grade picaridin administered at the rate of 50 mg/cm.
  • Researchers noted a 39-year-old man developed an allergic reaction of contact dermatitis several hours after using repellent containing 10% picaridin.
  • There are no reported cases of major effect or death after the use of picaridin.

Treatment of dermal irritation caused by picaridin clean your skin with mild soap and lukewarm water to remove any irritants. Stop using picaridin and apply bland petroleum jelly like Vaseline to soothe the area. Try using anti-itch treatments such as calamine lotion or hydrocortisone cream (Cortisone-10).



  1. “Icaridin.” ChemSpider,
  2. “Icaridin.” Uses, Interactions, Mechanism of Action | DrugBank Online,
  3. “Picaridin.” National Pesticide Information Center,
  4. “Picaridin.” National Pesticide Information Center,,liquids%2C%20aerosols%2C%20or%20wipes.