Heliotrope thrives on bare ground, such as along roadsides, fallowed ground and amongst stubbles.

Livestock tend to avoid eating heliotrope if other feed is available, because heliotrope is relatively unpalatable. Sheep are primarily affected because they are most often grazed in the locations where heliotrope is found.

The toxin found in heliotrope alters the liver's metabolism for copper causing the liver to hold abnormally high levels of copper. 

When the liver becomes saturated with copper there is a rapid release of copper leading to kidney failure and death due to a condition commonly known as ‘yellows’. This usually does not occur until sheep have been exposed to heliotrope for more than one summer.

Yellows often occurs after the heliotrope exposure, when sheep are later put on lush pastures which are rich in copper, such as clover.