Chamomile

The ASPCA lists chamomile (Anthemis nobilis, the Roman chamomile) as toxic to cats and dogs, and to horses: skin irritation, vomiting, diarrhoea and loss of appetite. The tea chamomile grown here is German chamomile (Matricaria), a different genus that the ASPCA does not list by name. It is a close daisy-family relative that shares some of the same oils, so give it the same caution.

Chamomile tea is fine for most people. Anyone sensitive to its allergens can react with a rash, hives or a swollen mouth, and in some cases shortness of breath, so stop and get medical help if breathing is affected.