Select a Plant by:


Persea americana

(48K) (25K) (45K)

For additional images, click:

Select an image to see a magnified version. Note the file size beneath each image since large files will take longer to load from home with a modem.

DescriptionAvocado are trees or shrubs with dark green berries and large seeds.
Geographic rangeFound in southern North America and in the tropics.
Toxic principleUnidentified toxin has a direct effect on the myocardium as well as on tissues of the lactating mammary gland.
ToxicityFresh and dried leaves, bark, skin, and seeds are toxic to cattle, goats, horses, rabbits, birds, and fish.  Severe mastitis may result in lactating goats fed 20g leaves/kg body weight.  Doses of 30g leaves/kg body weight or more can cause edema and cardiomyopathy.

Clinical signs. At lower doses, non-infectious mastitis is seen with a 75% decrease in milk production and watery, cheesy, curdled milk.  Higher doses can cause edema of the head and neck leading to upper respiratory distress in horses.  Colic is occasionally seen.

Laboratory Diagnosis. Elevation of serum enzymes creatinine phosphokinase and aspartate aminotransferase.

LesionsIn rabbits and goats, brisket and neck edema are seen in addition to acute pulmonary edema caused by cardiomyopathy and heart failure.  Lung congestion, hydropericardium, and subcutaneous edema in the pectoral region are seen.

Treatment is supportive.  Relieve signs with non-steroidal anti-inflammatories and diuretics.  Administer antibiotics to control secondary infections of the mammary gland.
PreventionDo not allow horses and livestock access to avocado trees and shrubs.  Do not feed avocado seeds or fruits to pet birds.


Copyright 2002

University of Pennsylvania
Created by:    Alexander Chan (2003), Daphne Downs (2002), Chris Tsai (2001), Brett Begley (2000), Janet Triplett (1997)
Faculty Advisor:  Dr. Robert Poppenga