Ouabain is a toxic compound derived from the seeds of certain plants, particularly from the African tree species Strophanthus. It has been traditionally used as a poison for hunting and as a medicinal agent in some cultures. In modern medicine, ouabain is studied for its effects on the heart, as it can inhibit the sodium-potassium ATPase enzyme, leading to increased heart contractility. However, its use is limited due to its toxicity and potential side effects, making it important to use caution when considering its applications.