There are several species of chamomile, but the one commonly used in herbal teas is Matricaria recutita.

Feverfew is a different plant (Tanacetum parthenium), typically utilized as a migraine preventative.

Yes - big difference. The flowers look somewhat alike at first glance, but they are very different plants.

Chamomile is a mild relaxing herb, and is often used for teas. Almost every large grocery store in the US has some kind of chamomile tea.

Feverfew is most commonly used for fevers, migraine, and arthritis. The name is related to the word febrifuge, which means to break a fever.

The wikipedia pages for these herbs are OK - they give a basic description, and I didn't see any glaring errors, although they are rather brief and not a thorough discussion.

http://en.wikipedia.org/wiki/Feverfew
http://en.wikipedia.org/wiki/Matricaria_recutita

where Can i find the fresh leaf? in term of capsule, which one is most potent?

Both are very easy to grow and could be added to your flower gardens since they have pretty daisy-like flowers - as long as you don't use chemicals on your gardens. That would be the best source I know of for fresh leaf!

FataMorgana

By the way, one similarity between chamomile and feverfew is that both plants ae members of the Compositae, and can trigger allergic reactions in susceptible people.

One person I recommended feverfew to for lessening frequency of migraines had to discontinue it after a few days, because she developed an itchy rash.

In addition to herbal uses, feverfew does make a good garden plant (long flowering period, self-seeds and easy to transplant around as a filler where needed).