Two forms of vitamin A are available in the human diet: preformed vitamin A (retinol and its esterified form, retinyl ester) and provitamin A carotenoids [1-5]. Preformed vitamin A is found in foods from animal sources, including dairy products, fish, and meat (especially liver).
Rabbit tobacco can be used medicinally in several ways. Smoking the leaves is good for sinusitis, head colds, and congestion. In hot teas, it is used to treat sore throats, fevers, diarrhea, colds, flu, pneumonia, asthma, and coughs, as well as a mild nerve sedative, a diuretic, and an antispasmodic.
An approximate amount to feed would be around 1 cup of greens for 2 lbs of rabbit body weight once a day or divided into multiple feedings a day. Many plants contain a naturally occurring chemicals called an alkaloids, which are mild toxins that protect plant in the wild.