You collect the three ingredients (coconut milk, bone, and key ingredient) and bring them to him atop his bamboo tree hut. He will mix the ingredients into a sleeping potion that will put Booga the shark to sleep.
You must wear a grass skirt when you visit him, as he doesn't like foreigners.
Shark Tooth Island
The medicine man makes you a potion in a coconut. Shoot it at the shark and it will fall asleep. Swim to the island on the right.
When you have sedated the shark, you can swim out to the island in Booga Bay to bring him back.
You use it to make the medicine for The great Booga
you have go into that really big tree
You keep it until the medicine man uses it.
The mission on Shark Tooth Island is to rescue the boy who is stranded in an island in Booga Bay (far right of the island) by the giant shark Booga. The solution is to gather the ingredients for a sleeping potion, to be mixed by the island's medicine man. (see related question)
Shark tooth island is when you have to to save people from a giant shark
The medicine man is the person in the palm tree next to the Ancient Ruins.
You wear a grass skirt from a stall
A coconut bone and secret ingredient
you have to wear the grass skirt