Grapefruit seed extract is an extract from the seeds of the grapefruit. It is an excellent remedy for skin diseases, external injuries, fungal infections, and can be used internally for the diseases caused by parasites, bacteria, and viral or fungal infections. It can help pets combat giardia or beaver fever. People who are worried about bacteria in raw food may add a few drops into the food as well. It can be mixed into food, water, shampoo, ear washes, cat litter, bedding and has numerous other applications.