Speak to Trufitus in Tai Bwo Wannai Village. He will ask you to make him a potion. You will need five herbs to make this potion.
He will ask you to gather some snake weed. "It grows near vines in an area to the south west where the ground turns soft and the water kisses your feet."
You will want to 'Search Marshy jungle vine' for the snake weed. You will get a grimy herb. Clean it for the snake weed. Take this back to Trufitus.
He will now ask you to get him some Ardrigal. "It is related to the palm and grows to the east in its brother's shady profusion. To the east you will find a small peninsula, it is just after the cliffs come down to meet the sands, here is where you should search for it."
Head to the palm tree shown in the key above, and search it. You will receive a grimy herb yet again. Clean it and return to Trufitus.
He will now ask you to get Sito Foil. "...and it grows best where the ground has been blackened by the living flame."
Head to the place marked on the key. 'Search Scorched earth.' You will get a grimy herb. Clean it and take it back to Trufitus.
He will now ask you to get Volencia moss. "It clings to rocks for its existence. It is difficult to see, so you must search for it well. It prefers rocks of high metal content and a frequently disturbed environment. There is some, I believe to the south east of this village."
Head to the place marked on the key. You will need to search the rocks in the north east corner of the pit. Clean the grimy herb and take it back to Trufitus.
"This is the most difficult to find as it inhabits the darkness of the underground. It is called Rogues Purse, and is only to be found in pothole caverns in the northern part of this island. A secret entrance to the pothole caverns is set into the northern cliffs of this land. Take care Bwana as it may be dangerous."
Head to the place marked on the key. Search the rocks here and you will be able to enter the cavern. Search the fungus covered walls in the cave and you will receive a grimy herb. Clean it and return to Trufitus.