Green Grows the Toxins

Rodenticide (rat and mouse bait):

Green or turquoise coloring is common for these baits. Be advised that the active ingredient cannot be determined by appearances alone. The poison could be bromethalin, which causes swelling of the brain and spinal cord; cholecalciferol (vitamin D3), which can cause high calcium leading to kidney failure and other signs; or an anti-coagulant that can cause a bleeding disorder. These poisons can cause signs after one ingestion or after chronic ingestion.

In the Kitchen:

  • The avocado plant and fruit can be very toxic to birds and rabbits. Dogs are more at risk of getting the pit stuck in their intestines (foreign body obstruction).
  • Green grapes (really grapes of any color) should be avoided. This fruit may be able to cause significant vomiting, diarrhea, and possibly kidney failure.
  • Moldy cheese and compost can contain mycotoxins, which can cause persistent tremors or liver failure.

Although most exposures are to the extract (∆8- and ∆9-THC) rather than the plant itself, marijuana is a common threat to our pets. Vape liquids, edibles, tinctures, and joints cause signs at almost any dose. Animals may urinate on themselves, have tremors, and be unable to regulate their temperatures.


Daylilies and crocuses are some of the first plants that we see emerging from the ground. Daylilies are similar to Asiatic lilies (Lilium sp.) that grow later in the season or are in floral bouquets – both varieties can cause kidney failure in cats. Spring-growing crocuses are much less dangerous than their Autumn cousins and may cause mild GI signs (nausea, diarrhea).

Blue-green algae blooms tend to occur in late summer through early winter in northern US and all year long in southern US. The water turns a pea-green and has thick mats of green or blue-green algae on the surface. Depending on which toxin is in the algae, liver failure or seizures could occur.


Written by:

Heather Handley, DVM