Shelter Health

The Two Most Common St. Patrick’s Day Toxins

When you think of St. Patrick’s Day, you probably think of a few things: shamrocks, alcohol and the color green. While FD&C Green No. 3 is generally regarded as safe (GRAS) by the FDA, do you know what to do if you get calls from worried clients about the other two?


Many dogs (and some cats) will happily lap up beer (green or not) that is left within reach, and the ASPCA Animal Poison Control center notes that St. Patty’s day parties are a very common time for pets to get into unattended drinks.

The onset of action with alcoholic beverages is typically fast (within 30 minutes, potentially faster with higher dosages) so the opportunity for emesis with alcohol is often very short and is not recommended in symptomatic pets. 

Ethanol intoxication can cause ataxia, depression, recumbency, hypothermia, disorientation, vocalization, acidosis, tachycardia, dyspnea, aspiration pneumonia, tremors, coma and seizures.


The name “shamrock” can refer to several different plants, and it is always important to identify them by their scientific names to assess the risk. When we get a call about a shamrock around St. Patrick’s Day, Oxalis acetosella is typically the plant in question.

The toxic principle of Oxalis is oxalates. The majority of the oxalates are insoluble calcium oxalate crystals, which act locally to irritate the mucous membranes. The insoluble crystals can cause oral pain, hypersalivation, vomiting, diarrhea and/or swelling in the oral cavity, pharynx and tongue. If significant swelling occurs, it would be possible, though extremely rare, to see dyspnea or airway obstruction.

Some of the oxalates present within the Oxalis plant are soluble. Soluble oxalates freely enter the bloodstream and combine with calcium, which can cause hypocalcemia. We can see vomiting, ataxia, weakness, panting, facial rubbing, muscle fasciculations and seizures. Renal damage is due to both the calcium oxalate crystal formation and direct cellular and vascular damage of the oxalates.

Despite how scary this sounds, most companion animals are unable to get into a large enough amount of plant material to cause systemic signs. Many pets who ingest a small amount of plant material can be monitored at home; pets who ingest larger amounts of plant material and are at risk of hypocalcemia may need emesis induced and/or monitoring at the hospital. While this can be deadly in grazing animals, cases of true toxicity leading to hypocalcemia are rare in companion animals.

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