Here's an image of bittermelon, or ampalaya in Tagalog language. The name says something about this vegetable, and yes it is bitter.

Above shows the flowers and two bittermelon. It is a vine and grows on Summer. In the Philippines, both the leaves and the fruit is eaten as a vege. It helps on colds, coughs, weak body, and I have even use the leaves sap for my asthma. It is not my favorite vege but I can deal with its bitterness when I'm sick ^.^